To be clear, if i need to apply this NVL function to more than one column like this: Answer: You will need to make separate NVL function calls for each column. A scalar variable declaration that specifies NOT NULL, either implicitly or explicitly, must assign an initial value to the variable (because the default initial value for a scalar variable is NULL). The SQL expressions are evaluated, and their values appear in the results of the query. You can connect to Oracle Database as the user HR only if the HR account is unlocked. If you do, an error occurs when you reference the duplicate identifier. Suppose that an employee receives his or her first check on the last day of the month in which he or she was hired. In Example 2-42, short-circuit evaluation prevents the OR expression from causing a divide-by-zero error. Character functions accept character input. Example 2-1 Valid Case-Insensitive Reference to Quoted User-Defined Identifier, Example 2-2 Invalid Case-Insensitive Reference to Quoted User-Defined Identifier, Example 2-3 Reserved Word as Quoted User-Defined Identifier, Example 2-4 Neglecting Double Quotation Marks. The conditional compilation feature and related PL/SQL packages are available for Oracle Database 10g Release 1 (10.1.0.4) and later releases. Example 2-60 Displaying Post-Processed Source Textsource text. The DECODE function compares a value or expression to search values, and returns a result when it finds a match. When referencing an identifier, you use a name that is either simple, qualified, remote, or both qualified and remote. A static constant is declared in a package specification with this syntax: The type of static_expression must be the same as data_type (either BOOLEAN or PLS_INTEGER). Do not embed any others characters (including whitespace characters) inside a delimiter. Aggregate functions are especially powerful when used with the GROUP BY clause, which groups query results by one or more columns, with a result for each group. A query nested within another SQL statement is called a subquery. For example, these expressions are true: To make comparisons both case-insensitive and accent-insensitive, append _AI to the value of the NLS_SORT parameter (for example, BINARY_AI or FRENCH_M_AI). A BOOLEAN expression is an expression that returns a BOOLEAN valueTRUE, FALSE, or NULL. The functions UPPER, INITCAP, and LOWER display their character arguments in uppercase, initial capital, and lowercase, respectively. Learn the cause and how to resolve the ORA-00984 error message in Oracle. Example 4-5 Selecting Data for Last Names that Start with the Same Substring. Thank you Lucas for showing us this nifty trick. Because a selection directive needs a BOOLEAN static expression, you cannot use $$PLSQL_UNIT, $$PLSQL_UNIT_OWNER, or $$PLSQL_UNIT_TYPE in a VARCHAR2 comparison such as: However, you can compare the preceding directives to NULL. To reference the global identifier, the subunit must qualify it with the name of the unit that declared it. Example 2-59 Compiling Different Code for Different Database Versions. The selector is grade. This SQL programming tutorial site lists commonly-used SQL statements, and is divided into the following sections: SQL Commands: Basic SQL statements for storing, retrieving, and manipulating data in a relational database. Where x and y are PLS_INTEGER static expressions: For information about PLS_INTEGER static expressions, see "PLS_INTEGER Static Expressions". A constant holds a value that does not change. You cannot declare the same identifier twice in the same PL/SQL unit. The second label appears again in the inner block. Second, the for clause shows for state_code in (any) instead of a long list of state_code values. For example, the identifiers lastname, LastName, and LASTNAME are the same. For the kinds of items that can be referencing and referenced items, see "%TYPE Attribute". Finally, the operation 21/7 is evaluated, producing the final value 3. Help us identify new roles for community members, Proposing a Community-Specific Closure Reason for non-English content. To understand Example 4-26, you must understand the JOB_HISTORY table. Lines of code in "Example 2-59" that are not included in the post-processed text appear as blank lines. Either type the full path after the prompt or browse to it, and then press the key Enter. Activate debugging or tracing statements in the development environment and hide them when running the application at a production site. SQL> SELECT id, DECODE(col1, NULL, 'ZERO', col1) AS output FROM null_test_tab ORDER BY id; ID OUTPUT ----- ----- 1 ONE 2 ZERO 3 ZERO 4 ZERO 4 rows selected. Since web search for Oracle case tops to that link, in Oracle SQL? If you use constant_name in the BOOLEAN expression in a conditional compilation directive in a PL/SQL unit, then the PL/SQL unit depends on the package package_name. At the SQL> prompt, unlock the HR account and reset its password: The HR account is unlocked and its password is password. While using this site, you agree to have read and accepted our Terms of Service and Privacy Policy. Example 2-19 Qualifying Identifier with Subprogram Name. In PL/SQL expressions, you can use all SQL functions except: Aggregate functions (such as AVG and COUNT), Analytic functions (such as LAG and RATIO_TO_REPORT), Data mining functions (such as CLUSTER_ID and FEATURE_VALUE), Encoding and decoding functions (such as DECODE and DUMP), Model functions (such as ITERATION_NUMBER and PREVIOUS), Object reference functions (such as REF and VALUE), XML functions (such as APPENDCHILDXML and EXISTSNODE). Table 2-3 shows operator precedence from highest to lowest. The subquery_factoring_clause lets you assign a name (query_name) to a subquery block.You can then reference the subquery block multiple places in the query by specifying query_name.Oracle Database optimizes the query by treating the query_name as either an inline view or as a temporary table. Example 2-16 Declaring Variable of Same Type as Another Variable. This example sets the values of the user-defined inquiry directives $$my_debug and $$my_tracing and then uses conditional compilation: In the specification of package my_pkg, to determine the base type of the subtype my_real (BINARY_DOUBLE is available only for Oracle Database versions 10g and later. Because the sub-blocks are at the same level, the first sub-block cannot reference d, and the second sub-block cannot reference c. Example 2-18 Qualifying Redeclared Global Identifier with Block Label. In the below example we are going to drop the after delete trigger. In addition to the ANY clause, you can write a subquery. The functions LTRIM and RTRIM trim characters from the left and right ends of their character arguments, respectively. For this explanation, assume that a simple CASE expression has this syntax: The selector is an expression (typically a single variable). DDL code. Here is the example: The output comes back as CLOB so make sure the LONGSIZE is set to a large value before running the query. As stated in "Selecting Data that Satisfies Specified Conditions", the condition in the WHERE clause can be any SQL condition. Use synonyms for the keyword you typed, for example, try "application" instead of "software. The query in Example 4-37 uses the COUNT function and the GROUP BY clause to show how many people report to each manager. This example invokes the print_boolean procedure from Example 2-35 to print the values of expressions that use relational operators to compare arithmetic values. For step3, you need a user name and password. If that unit has subunits, the identifier is global to them. To close this pane, click the x to the right of the name EMPLOYEES. Oracle Database SQL Language Reference for more information about LIKE, Oracle Database SQL Language Reference for information about REGEXP_LIKE, which is similar to LIKE. A pane appears with a tab labeled hr_conn and two subpanes, Worksheet and Query Builder. For example, this command sets the value of $$flag to 5 and its data type to PLS_INTEGER: Oracle recommends against using PLSQL_CCFLAGS to assign values to predefined inquiry directives, including compilation parameters. Using Transact-SQL Execute a stored procedure. Check the spelling of your keyword search. The query in Example 4-25 uses the SUBSTR function in the WHERE clause to select the employees whose JOB_ID starts with 'SH', and uses the REPLACE function to replace 'SH' with 'SHIPPING' in each such JOB_ID. From the Standard bar, select New Query. The character immediately after an escape character is interpreted as a literal. The NVL function can be used in the following versions of Oracle/PLSQL: Let's look at some Oracle NVL function examples and explore how to use the NVL function in Oracle/PLSQL. For this explanation, assume that a searched CASE expression has this syntax: The searched CASE expression returns the first result for which boolean_expression is TRUE. A selection directive selects source text to compile. For more information about the concatenation operator, see "Concatenation Operator". This table summarizes the relational operators. The query in Example 4-43 returns the last name and commission of the employees whose last names begin with 'B'. It is easy for humans to read and write. So, You still have the opportunity to move ahead in your career in Oracle PL SQL Development. For example: SELECT NVL(supplier_city, 'n/a') FROM suppliers; The SQL statement above would return 'n/a' if the supplier_city field contained a null value. For information about implicit data conversion, see Oracle Database SQL Language Reference. In a crosstab report, you want to transpose the Times Purchased column to the header row as shown in Figure 2. If you are connected to the database, the hr_conn information expands (see the information that follows "Click OK" in step2). Example 2-20 Converting Dates to Characters Using a Format Template. Example 2-16 Concatenating Character Data. The character functions that SQL supports are listed and described in Oracle Database SQL Language Reference. The hr_conn information expands: The plus sign becomes a minus sign (-), and under the hr_conn icon, a list of schema object types appearsTables, Views, Indexes, and so on. Example 2-21 Converting Characters to Numbers, Oracle Database SQL Language Reference for more information about SQL conversion functions. Example 4-20 Concatenating Character Data. One data type is compatible with another data type if it can be implicitly converted to that type. Because the aliases are not enclosed in double quotation marks, they are displayed in uppercase letters. The New/Select Database Connection window closes. To select all columns of the EMPLOYEES Table: If a pane with the tab hr_conn is there, select it. The DBMS_PREPROCESSOR package provides subprograms that retrieve and print the source text of a PL/SQL unit in its post-processed form. In the procedure circle_area, to compile some code only if the inquiry directive $$my_debug has the value TRUE. As Table 2-4 and Example 2-35 show, AND returns TRUE if and only if both operands are TRUE. A quoted user-defined identifier is case-sensitive, with one exception: If a quoted user-defined identifier, without its enclosing double quotation marks, is a valid ordinary user-defined identifier, then the double quotation marks are optional in references to the identifier, and if you omit them, then the identifier is case-insensitive. How to connect 2 VMware instance running on same Linux host machine via emulated ethernet cable (accessible via mac address)? In Example 2-2, the reference "Hello" is invalid, because the double quotation marks make the identifier case-sensitive. It knew that from the following clause in the query: for state_code in ("New York","Conn","New Jersey","Florida","Missouri"). This section assumes that SQLDeveloper is installed on your system, and shows how to start it and connect to Oracle Database Express Edition. The abbreviations may be self explanatory but suppose you want to display the state names instead of abbreviations, ("Connecticut" instead of "CT")? The SQL statement above would return 'n/a' if the supplier_city field contained a null value. Copyright 2003-2022 TechOnTheNet.com. Otherwise, it would return the supplier_city value. FM removes leading and trailing blanks from the month name. Example 2-3 declares quoted user-defined identifiers "BEGIN", "Begin", and "begin". You can connect to Oracle Database Express Edition only through a client program, such as SQL*Plus or SQLDeveloper. Therefore, the first sub-block cannot reference the global variable a; it can reference only its local variable a. Under "Enter SQL Statement:" is a field where you can enter a SQL statement. This tutorial shows how to use SQLDeveloper to view the objects that belong to the HR schemathat is, how to browse the HR schema. To connect to Oracle Database Express Edition from SQLDeveloper: For instructions, see Oracle SQL Developer User's Guide. Summary: in this tutorial, you will learn how to use the Oracle DECODE() function to embed if-then-else logic in SQL queries.. Introduction to Oracle DECODE() function. To select all columns of the EMPLOYEES Table: In the field under "Enter SQL Statement:", enter this query: This tutorial shows how to select only the columns FIRST_NAME, LAST_NAME, and DEPARTMENT_ID of the EMPLOYEES table. The query in Example 4-24 uses SUBSTR to abbreviate FIRST_NAME to first initial and to strip the area code from PHONE_NUMBER. In regular SQL, you can issue the following statement: This is the information you want but it's a little hard to read. The RANK function returns the relative ordered rank of a number, and the PERCENT_RANK function returns the percentile position of a number. If this is the first time you have started SQLDeveloper on your system, you are prompted to enter the full path to java.exe (for example, C:\Program Files\Java\jdk1.6.0_021\bin\java.exe). For expression syntax, see Expression. ), Oracle SQL Developer User's Guide for more information about the SQLDeveloper user interface, "About Sample Schema HR" for general information about schema HR. The parentheses in the second invocation change the order of operation. In the following example, the Oracle DECODE() function compares the first argument (1) with the second argument (1). The following query selects the first name, last name, and job title of that employee: When used with the DISTINCT option, the COUNT function shows how many distinct values are in a data set. In the regular expression (_m[an|gr]), the metacharacter | indicates the OR condition. Suppose you have a list of preferred states and you want to select the rows for those states only. In this example, the variable surname inherits the data type, size, and NOT NULL constraint of the variable name. How is this different than the top voted answer? The query in Example 4-29 uses the ADD_MONTHS function to show the first evaluation day for each employee in department 100. Or you can use the reverse operation of pivot UNPIVOTto break up the columns to become rows, as is possible in Oracle Database 11g. The SQL statement appears in a pane named EMPLOYEES. For information about this parameter, see "Assigning Values to Inquiry Directives" and Oracle Database Reference. To connect to Oracle Database Express Edition as user HR from SQLDeveloper: Follow the directions in "Connecting to Oracle Database Express Edition from SQLDeveloper", entering the following values at steps3: (You can enter a different name, but the tutorials in this document assume that you named the connection hr_conn.). Example 4-8 Selecting All Managers in the EMPLOYEES Table. You can also use parentheses to improve readability, as in Example 2-32, where the parentheses do not affect evaluation order. The item can acquire this constraint either implicitly (from its data type) or explicitly. FIRST_NAME and LAST_NAME are in the EMPLOYEES table, and DEPARTMENT_NAME is in the DEPARTMENTS table. This example invokes the print_boolean procedure from Example 2-35 to print the values of expressions that include the IN operator. Oracle 9i extended its support to PL/SQL to allow CASE to be used as an expression or and CASE Statements ; Value Match (Simple) CASE Expression. If the Oracle pane is not showing, click the tab Oracle. Please re-enable JavaScript in your browser settings. Here is the output: As you can see, the column STATE_CODE_XML is XMLTYPE, where the root element is . There cannot be space between $ and plsql_identifier. Example 2-7 Selecting Data from One Department. When using character literals in PL/SQL, remember: For example, these literals are different: PL/SQL has no line-continuation character that means "this string continues on the next source line." A better way to represent the same data may be through the use of crosstab reports, in which you can organized the data vertically and states horizontally, just like a spreadsheet: Prior to Oracle Database 11g, you would do that via some sort of a decode function for each value and write each distinct value as a separate column. This example uses a SELECT INTO statement to assign to the variable bonus the value that is 10% of the salary of the employee whose employee_id is 100. Under the Worksheet, the Query Result pane appears, showing all columns of the EMPLOYEES table. The query in Example 2-27 uses a simple CASE expression to show the country name for each country code. By default, it is deselected. ". Most return character values, but some return numeric values. Example 2-3 Viewing EMPLOYEES Table Properties with SQL*Plus. (Example 2-37 invokes the print_boolean procedure from Example 2-35.). "Connecting to Oracle Database Express Edition as User HR from SQLDeveloper", "About SQLDeveloper" for a brief description of SQLDeveloper, Oracle SQL Developer User's Guide for more information about using SQLDeveloper to create connections to Oracle Database Express Edition. This example declares several variables with scalar data types. Example. Example 4-3 Selecting Data from One Department. For information about the SYSTIMESTAMP function, see Oracle Database SQL Language Reference. For information about the EXTRACT function, see Oracle Database SQL Language Reference. I want to be able to quit Finder but can't edit Finder's Info.plist after disabling SIP, What is this fallacy: Perfection is impossible, therefore imperfection should be overlooked, central limit theorem replacing radical n with n, MOSFET is getting very hot at high frequency PWM. Example 2-2 shows how to view the names and data types of the objects that belong to the HR schema. Advanced SQL: Discusses SQL commands and calculations that are more advanced. The SQLWorksheet pane appears. Example 2-8 Selecting Data for Last Names that Start with the Same Substring. This example invokes the print_boolean procedure from Example 2-35 to print the values of expressions that include the BETWEEN operator. The initial value of area depends on the previously declared constant pi and the previously initialized variable radius. For information about PL/SQL units, see "PL/SQL Units and Compilation Parameters".. Predefined identifiers are declared in the predefined package STANDARD. For instance. Beginners should start with this section. This example declares three constants with scalar data types. You can assign values to inquiry directives with the PLSQL_CCFLAGS compilation parameter. When query results are displayed, records can be in any order, unless you specify their order with the ORDER BY clause. NOT NULL returns NULL, because NULL is an indeterminate value. The option(s) to resolve this Oracle error are: This error most commonly occurs when you try to include a column name in the VALUES clause of a INSERT statement. Cause. At the command prompt, type sqlplus and then press the key Enter. The expression x will only be evaluated once. Fortunately, you now have a great new feature called PIVOT for presenting any query in the crosstab format using a new operator, appropriately named pivot . If you use a package with static constants to control conditional compilation in multiple PL/SQL units, Oracle recommends that you create only the package specification, and dedicate it exclusively to controlling conditional compilation. This SQL Pretty Print support Pretty Print SQL Query syntax. The simple CASE expression returns the first result for which selector_value matches selector. The LIKE operator compares a character, string, or CLOB value to a pattern and returns TRUE if the value matches the pattern and FALSE if it does not. Results depend on current SYSTIMESTAMP value, but have this format: Conversion functions convert one data type to another. According to research, Oracle PL SQL has a market share of about 2.2%. The syntax for declaring a variable of the same type as a column is: "Declaring Items using the %ROWTYPE Attribute", which lets you declare a record variable that represents either a full or partial row of a database table or view, Example 2-15 Declaring Variable of Same Type as Column. Example 2-43 Relational Operators in Expressions. The query in Example 2-5 selects the same columns as the query in "Tutorial: Selecting Specific Columns of a Table", but it also specifies aliases for them. Each selector_value and each result can be either a literal or an expression. Using a conditional compilation directive to change the attribute structure of a type can cause dependent objects to "go out of sync" or dependent tables to become inaccessible. This example generates an error message if the database version and release is less than Oracle Database 10g Release 2; otherwise, it displays a message saying that the version and release are supported and uses a COMMIT statement that became available at Oracle Database 10g Release 2. To create a synonym, use the SQL statement CREATE SYNONYM, explained in Oracle Database SQL Language Reference. Real numbers are stored as approximate values, so Oracle recommends comparing them for equality or inequality. "Scalar Variable Declaration" for scalar variable declaration syntax, PL/SQL Data Types for information about scalar data types, PL/SQL Collections and Records, for information about composite data types and variables. Example. For information about the ADD_MONTHS function, see Oracle Database SQL Language Reference. In this example, the procedure check_credit declares a variable, rating, and a function, check_rating. Any comparison with NULL returns NULL. You can declare the same identifier in two different units. PL/SQL uses the database character set to represent:. In the Worksheet, you can enter a SQL statement. For more information about the SHOW command and its PARAMETERS option, see SQL*Plus User's Guide and Reference. The XML notation allows you to use the ANY keyword and you don't need to enter the state_code values. How do I UPDATE from a SELECT in SQL Server? Oracle Database SQL Language Reference for more information about queries and subqueries, Oracle Database SQL Language Reference for more information about the SELECT statement, SQL*Plus User's Guide and Reference for more information about the SQL*Plus command line interface, Oracle SQL Developer User's Guide for information about using the Worksheet in SQLDeveloper. Character comparisons are affected by NLS parameter settings, which can change at runtime. A set of character codes is called a character set. The query_name is subject to the same naming The REPLACE function replaces one substring with another. Without that, your answer has much less educational value - remember that you are answering the question for readers in the future, not just the person asking now! "Declaring Associative Array Constants" for information about declaring constant associative arrays, "Declaring Record Constants" for information about declaring constant records. How do I limit the number of rows returned by an Oracle query after ordering? For example, these expressions are true: To make comparisons case-insensitive, append _CI to the value of the NLS_SORT parameter (for example, BINARY_CI or XGERMAN_CI). Example 4-30 Displaying System Date and Time. subquery_factoring_clause. The table in the FROM clause of the query, DUAL, is a one-row table that Oracle Database creates automatically along with the data dictionary. Why do American universities have so many general education courses? Ready to optimize your JavaScript with Rust? Example 2-25 Substituting a String for a NULL Value. The third function parameter, 'i', specifies that the match is case-insensitive. Example 4-25 Replacing Substrings in Character Data. For information about the DBMS_PREPROCESSOR package, see Oracle Database PL/SQL Packages and Types Reference. For information about wrapping PL/SQL source text, see PL/SQL Source Text Wrapping. The Results pane appears, showing the result of the query. You can use this operator to combine information from two columns or expressions in the same column of the report, as in the query in Example 2-16. However, this NULL value is not the BOOLEAN value NULL. Question: I tried to use the NVL function through VB to access Oracle DB. The tablespace mytblspace is created and comprises one data file of size 200 MB contained in the disk group data . Example 2-34 creates a procedure, print_boolean, that prints the value of a BOOLEAN variable. Any number. Character values of data types CHAR, VARCHAR2, CLOB, and LONG. ), As Table 2-4 and Example 2-37 show, NOT returns the opposite of its operand, unless the operand is NULL. This section shows how to connect to Oracle Database Express Edition as the user HR from SQLDeveloper. The SYSDATE function returns the current date of the system clock as a DATE value. Debian/Ubuntu - Is there a man page listing all the version codenames/numbers? If a match is not found, then DECODE returns the default value, or NULL (if a default value is not specified). Example 2-1 Connecting to Oracle Database from SQL*Plus, "Connecting to Oracle Database Express Edition as User HR from SQL*Plus", "About SQL*Plus" for a brief description of SQL*Plus, SQL*Plus User's Guide and Reference for more information about starting SQL*Plus and connecting to Oracle Database Express Edition. PL/SQL also supports these character sets. When the value of on_hand is zero, the value of the left operand is TRUE, so PL/SQL does not evaluate the right operand. To test whether a value is NULL, use IF value IS NULL, as in these examples: Example 2-14, "Variable Initialized to NULL by Default", Example 2-34, "Procedure Prints BOOLEAN Variable", Example 2-53, "Searched CASE Expression with WHEN IS NULL". The query in Example 4-39 uses several aggregate functions to show statistics for the salaries of each JOB_ID. The query runs. The DECODE function is supported in the various versions of the Oracle/PLSQL, including, Oracle 12c, Oracle 11g, Oracle 10g and Oracle 9i. The sort criterion need not be included in the select list, as Example 4-15 shows. Example 4-7 Selecting Data that Satisfies Two Conditions, Oracle Database SQL Language Reference for more information about the SELECT statement, including the WHERE clause, Oracle Database SQL Language Reference for more information about SQL conditions. "BOOLEAN Data Type" for information about the BOOLEAN data type, String literal with maximum size of 32,767 bytes, TO_CHAR(x), where x is a PLS_INTEGER static expression. Here you specified that the values "New York", "Conn", and so on are values of a new column you want to be unpivoted on, called state_code. The query in Example 4-6 selects data only for employees whose last names include "ma". PL/SQL uses the national character set to represent character values of data types NCHAR, NVARCHAR2 and NCLOB. Conditional compilation lets you customize the functionality of a PL/SQL application without removing source text. This tutorial shows how to select only the columns FIRST_NAME, LAST_NAME, and DEPARTMENT_ID of the EMPLOYEES table. All conditional compilation directives are built from preprocessor control tokens and PL/SQL text. For example, 'a'||'b'='ab'. Now consider a case where you want to have a report of the purchase frequency each state - that is, how many customers bought something only once, twice, thrice and so on, from each state. Example 2-26 Assigning Value to Variable as IN OUT Subprogram Parameter. This example shows how to execute a (The initial value of a constant is its permanent value.). Conditional compilation directives are subject to these semantic restrictions. Example 2-3 shows how to view the properties of the EMPLOYEES table in the HR schema. For this attribute you can specify either the precision, which is the number of digits after the decimal point; or the currency code, which governs the Counterexamples to differentiation under integral sign, revisited, Books that explain fundamental chess concepts. SELECT OBJECT_NAME, OBJECT_TYPE FROM USER_OBJECTS, SELECT LAST_NAME, FIRST_NAME, PHONE_NUMBER FROM EMPLOYEES, WHERE (SALARY >= 11000) AND (COMMISSION_PCT IS NOT NULL), WHERE EMPLOYEES.DEPARTMENT_ID = DEPARTMENTS.DEPARTMENT_ID, (EXTRACT(YEAR FROM SYSDATE) - EXTRACT(YEAR FROM HIRE_DATE)), NVL(TO_CHAR(COMMISSION_PCT), 'Not Applicable'), NVL2(COMMISSION_PCT, SALARY + (SALARY * COMMISSION_PCT), SALARY) INCOME, WHEN HIRE_DATE < TO_DATE('01-Jan-90', 'dd-mon-yy'), WHEN HIRE_DATE < TO_DATE('01-Jan-95', 'dd-mon-yy'), WHEN HIRE_DATE < TO_DATE('01-Jan-00', 'dd-mon-yy'), Oracle Database PL/SQL Language Reference, Description of the illustration success.gif, "Connecting to Oracle Database Express Edition from SQL*Plus", "Connecting to Oracle Database Express Edition from SQLDeveloper", "Tutorial: Viewing HR Schema Objects with SQLDeveloper", "Tutorial: Viewing EMPLOYEES Table Properties and Data with SQLDeveloper", "Tutorial: Selecting Specific Columns of a Table". Oracle 12c, Oracle 11g, Oracle 10g, Oracle 9i, Oracle 8i. For the complete syntax of a BOOLEAN expression, see "boolean_expression ::=". A national character literal is composed of characters in the national character set. A case-insensitive comparison treats corresponding uppercase and lowercase letters as the same letter. As the customer purchases more items from the store, the column times_purchased is updated. To connect to Oracle Database Express Edition from SQL Developer: Start SQL Developer.. For instructions, see Oracle SQL Developer User's Guide.. PL/SQL source text that uses only the basic characters can be stored and compiled in any database. For each DATE and time stamp value, Oracle Database Express Edition stores this information: For each time stamp value, Oracle Database Express Edition also stores the fractional part of the second, whose precision you can specify. JSON (JavaScript Object Notation) is a lightweight data-interchange format. Consider the case of a table named CUSTOMERS. This Oracle tutorial explains how to use the CURSOR FOR LOOP in Oracle with syntax and examples. How can I do 'insert if not exists' in MySQL? The query in Example 4-40 shows how much each department spends annually on salaries, but only for departments for which that amount exceeds $1,000,000. Therefore, expressions can be arbitrarily complex. Code: SELECT firstname,lastname FROM employees WHERE salary BETWEEN '12000' AND '15000'; In the above example, we tried to select only those employees whose salary lies in between 12000 and 15000. Pictorially, here is the how the traditional tabular format looks: Figure 1 Traditional tabular representation. A query, or SQL SELECT statement, selects data from one or more tables or views. Each character function returns a single value for each row that is evaluated. The datetime functions that SQL supports are listed and described in Oracle Database SQL Language Reference. To see more columns of the records, move the horizontal scroll bar to the right.). The NULL-related functions facilitate the handling of NULL values. For information about static constants, see "Static Constants". We suggest you try the following to help find what youre looking for: Present information in a spreadsheet-type crosstab report from any relational table using simple SQL, and store any data from a crosstab table to a relational table. Example 4-2 Preserving Case and Including Spaces in Column Aliases. If you alter the package specification, the dependent PL/SQL unit might become invalid and need recompilation (for information about the invalidation of dependent objects, see Oracle Database Development Guide). The following query is equivalent to the query in Example 2-12: To make queries that use qualified column names more readable, use table aliases, as in the following example: Although you create the aliases in the FROM clause, you can use them earlier in the query, as in the following example: The select_list of a query can include SQL expressions, which can include SQL operators and SQL functions. (To see all constraint properties, move the horizontal scroll bar to the right.). +1 especially for mentioning the worrying things about this schema. In this case, it is used in the file creation form. Both tables have DEPARTMENT_ID. Example 4-9 Selecting All Employees Whose Last Names Have Double Vowels. Therefore, character comparisons are evaluated at runtime, and the same character comparison can have different values at different times. This section shows how to start SQL*Plus and connect to Oracle Database Express Edition. PL/SQL uses the database character set to represent: For information about PL/SQL units, see "PL/SQL Units and Compilation Parameters". Numeric functions accept numeric input and return numeric values. Copyright 2003-2022 TechOnTheNet.com. You can use the query in Example 2-12. The alias renames the column for the duration of the query, but does not change its name in the database. The metacharacter [[:digit:]] represents a digit, the metacharacter {n} specifies n occurrences, and the metacharacter \ is an escape character. Example 2-41 invokes the print_boolean procedure from Example 2-35 three times. Example 2-18 Displaying the Number of Years Between Dates. Let's look at some Oracle NVL function examples and explore how to use the NVL function in Oracle/PLSQL. Oracle Database SQL Language Reference for more information about queries and subqueries, Oracle Database SQL Language Reference for more information about the SELECT statement, SQL*Plus User's Guide and Reference for more information about the SQL*Plus command line interface, Oracle Database SQL Developer User's Guide for information about using the SQLWorksheet in SQLDeveloper. The simplest expressions, in order of increasing complexity, are: A single constant or variable (for example, a), A unary operator and its single operand (for example, -a), A binary operator and its two operands (for example, a+b). At least one result must not be the literal NULL. A preprocessor control token identifies code that is processed before the PL/SQL unit is compiled. How do I import an SQL file using the command line in MySQL? The referencing item does not inherit the initial value of the referenced item. Therefore, after the sub-block redeclares the global variable birthdate, it can reference that global variable by qualifying its name with the block label. As you specified state_counts, that is the name of the new column created in the resultant output. The condition in the WHERE clause can be any SQL condition (for information about SQL conditions, see Oracle Database SQL Language Reference). Most return character values, but some return numeric values. When parentheses are nested, the most deeply nested operations are evaluated first. To control the order of evaluation, enclose operations in parentheses, as in Example 2-30. The PL/SQL data types include the SQL data types. The selection directive evaluates the BOOLEAN static expressions in the order that they appear until either one expression has the value TRUE or the list of expressions is exhausted. It might be easier to demonstrate this via an example. If an inquiry directive ($$name) cannot be resolved, and the source text is not wrapped, then PL/SQL issues the warning PLW-6003 and substitutes NULL for the value of the unresolved inquiry directive. All rights reserved. Therefore, the search pattern must be a regular expression, and you must use the REGEXP_LIKE function, as in Example 4-8. Later you used unpivot on the table CUST_MATRIX but that didn't get back the details of the original table CUSTOMERS. Example 2-23 Block with Multiple and Duplicate Labels. For this you use substring function. This example initializes the BOOLEAN variable done to NULL by default, assigns it the literal value FALSE, compares it to the literal value TRUE, and assigns it the value of a BOOLEAN expression. SQL*Loader Field List Reference The field-list portion of a SQL*Loader control file provides information about fields being loaded, such as position, data type, conditions, and delimiters. Example 2-55 Displaying Values of PL/SQL Compilation Parameters. The PL/SQL language fundamental components are explained. Example 2-6 has three single-line comments. Example 4-13 Reporting the Position of the First Space in Each STREET_ADDRESS, Oracle Database Advanced Application Developer's Guide for more information about using regular expressions in database applications, Oracle Database SQL Language Reference for syntax of regular expressions, Oracle Database SQL Language Reference for more information about the REGEXP_LIKE expression, Oracle Database SQL Language Reference for more information about the REGEXP_REPLACE expression, Oracle Database SQL Language Reference for more information about the REGEXP_SUBSTR expression, Oracle Database SQL Language Reference for more information about the REGEXP_COUNT expression, Oracle Database SQL Language Reference for more information about the REGEXP_INSTR expression. To the right of each column are its propertiesname, data type, and so on. If you continue a string on the next source line, then the string includes a line-break character. Each language might have different rules about where such characters occur in the collating sequence. The aggregate functions that SQL supports are listed and described in Oracle Database SQL Language Reference. The select_list specifies the columns from which the data is to be selected, and the source_list specifies the tables or views that have these columns.. A query nested within another SQL statement is called a Your local declaration overrides the global declaration (see "Scope and Visibility of Identifiers"). The DBMS_DB_VERSION package provides these static constants: The PLS_INTEGER constant VERSION identifies the current Oracle Database version. Datetime functions operate on date, timestamp, and interval values. The query in Example 2-19 uses the SYSTIMESTAMP function to display the current system date and time. You are in the SQLDeveloper environment. which is the ratio between the circumference and diameter. Oracle DECODE Function with NULL Values. For more information about the TIMESTAMP data type, see Oracle Database SQL Language Reference. In this example, the conditions in the loops are equivalent. FMMonth DD YYYY is an example of a datetime format model. Nilesh Barai. One number is greater than another if it represents a larger quantity. Identifiers name PL/SQL elements, which include: Every character in an identifier, alphabetic or not, is significant. What happens if you score more than 99 points in volleyball? The information in "Declaring Variables" also applies to constant declarations, but a constant declaration has two more requirements: the keyword CONSTANT and the initial value of the constant. This document explains how PL/SQL uses the database character set and national character set. For their descriptions, see "SQLCODE Function" and "SQLERRM Function". Example 4-24 Extracting Substrings from Character Data. Composed of characters from the database character set. The system connects you to an Oracle Database Express Edition instance. For more information about the BOOLEAN data type, see "BOOLEAN Data Type". The query in Example 4-19 uses the numeric function TRUNC to display the daily pay of each employee in department 100, truncated to the nearest dollar. A query, or SQL SELECT statement, selects data from one or more tables or views.. Static expressions are the only expressions that can appear in conditional compilation directives. By changing the value of the NLS_SORT parameter, you can perform comparisons that are case-insensitive and accent-insensitive. Also, depending on the number of status' you have you might want to consider turning this column into a foreign key to a separate table. A PL/SQL unit cannot reference identifiers declared in other units at the same level, because those identifiers are neither local nor global to the block. The query in Example 4-4 selects data only for employees in departments 100, 110, and 120. For more information about selecting from DUAL, see Oracle Database SQL Language Reference. Decode. The query in Example 4-31 uses the TO_CHAR function to convert HIRE_DATE values (which are of type DATE) to character values that have the format FMMonth DD YYYY. For a list of predefined identifiers, connect to Oracle Database as a user who has the DBA role and use this query: You can use predefined identifiers as user-defined identifiers, but it is not recommended. To search for the percent sign or underscore, define an escape character and put it before the percent sign or underscore. The query in Example 2-26 returns the last name, salary, and income of the employees whose last names begin with 'B', using the NVL2 function: If COMMISSION_PCT is not NULL, the income is the salary plus the commission; if COMMISSION_PCT is NULL, income is only the salary. At the password prompt, type your password and then press the key Enter. The concatenation operator (||) appends one string operand to another. If the right frame of SQLDeveloper shows the hr_conn pane: If the Worksheet subpane does not show, click the tab Worksheet. ), In the body of package my_pkg, to compute the values of my_pi and my_e differently for different database versions. Changing one does not affect the other, as this example shows. This example declares several variables (specifying initial values for some) and then uses assignment statements to assign the values of expressions to them. Answer: It is possible to the use the DISTINCT clause with the NVL function. Were sorry. The numeric functions that SQL supports are listed and described in Oracle Database SQL Language Reference. Because SQL does not have a BOOLEAN type, variable_name cannot be a BOOLEAN variable. Such a query is called a join. The SUBSTR function accepts as arguments a string, a character position, and a length, and returns the substring that starts at the specified position in the string and has the specified length. You can use a BOOLEAN variable itself as a condition; you need not compare it to the value TRUE or FALSE. Example 2-11 Scalar Variable Declarations. For more information about TO_CHAR, see Oracle Database SQL Language Reference.). Either the Connection Information window opens or the SQLWorksheet pane appears. Each BOOLEAN constant of the form VER_LE_v_r has the value TRUE if the database version is less than or equal to v and release is less than or equal to r; otherwise, it has the value FALSE. Scripting on this page enhances content navigation, but does not change the content in any way. The database character set can be either single-byte, mapping each First, you specified a clause, pivot xml, instead of just pivot. [1] It is stored in two locations: data dictionary tables (accessed via built-in views) and a metadata registry. If a subunit redeclares a global identifier, then inside the subunit, both identifiers are in scope, but only the local identifier is visible. 1. To select data only for employees in departments 100, 110, and 120, use this WHERE clause: The query in Example 2-8 selects data only for employees whose last names start with "Ma". For example: If an identifier is declared in a named PL/SQL unit, you can (and sometimes must) reference it with its qualified name. This tutorial shows how to select all columns of the EMPLOYEES table. Example 2-19 Displaying System Date and Time. The query in Example 2-21 uses the TO_NUMBER function to convert POSTAL_CODE values (which are of type VARCHAR2) to values of type NUMBER, which it uses in calculations. If the Connection Information window opens: In the Password field, enter the password for the user hr. Example 4-21 Changing the Case of Character Data. For information about pragmas, see: The PL/SQL compiler ignores comments. In Example 2-31, the operations (1+2) and (3+4) are evaluated first, producing the values 3 and 7, respectively. Example 2-21 Declaring Same Identifier in Different Units. You can use the REGEXP_REPLACE function, with regular expressions in the search pattern (the stored format) and references to those regular expressions in the replace string (the display format), as in Example 4-10. The simplest BOOLEAN expression is a BOOLEAN literal, constant, or variable. Example 2-2 Viewing HR Schema Objects with SQL*Plus, Oracle Database Reference for information about USER_OBJECTS, "Selecting Table Data" for information about using queries to view table data, "About Sample Schema HR" for general information about the schema HR. Reserved words and keywords are identifiers that have special meaning in PL/SQL. This example assigns the value of a searched CASE expression to the variable appraisal. Example 4-11 Extracting the Street Number from Each STREET_ADDRESS. The operations in an expression are evaluated in order of operator precedence. For more information, see "PL/SQL Units and Compilation Parameters". Scripting on this page enhances content navigation, but does not change the content in any way. This expression needs to be in the syntax of the query: The second line, "for state_code ," limits the query to only those values. Example 4-37 Counting the Number of Rows in Each Group. The variable name must be a valid user-defined identifier . Example #1 With integer or numerical values. This includes values returned by character functions and BOOLEAN expressions. To reference the global variable a, the first sub-block would have to qualify it with the name of the outer blockbut the outer block has no name. Here is an example of how you would combine the BETWEEN condition with the NOT Operator. Because a reserved word is not a valid ordinary user-defined identifier, you must always enclose the identifier in double quotation marks, and it is always case-sensitive. For information about datetime format models, see Oracle Database SQL Language Reference. The query in Example 4-45 uses a CASE expression to show proposed salary increases, based on length of service. If no selector_value matches selector, the CASE expression returns else_result if it exists and NULL otherwise. You must declare objects before you can reference them. Example 4-4 Selecting Data from Specified Departments. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Question: I need help with a SQL query. Example 4-43 Substituting a String for a NULL Value. Under the Worksheet, the Query Result pane appears, showing the query result. The data type can be any PL/SQL data type. For information about how PL/SQL resolves ambiguous names, see PL/SQL Name Resolution. Without the escape character, the metacharacter . The query in Example 4-44 returns the last name, salary, and income of the employees whose last names begin with 'B', using the NVL2 function: If COMMISSION_PCT is not NULL, the income is the salary plus the commission; if COMMISSION_PCT is NULL, income is only the salary. The text can be anything, but typically, it is either a statement (see "statement ::=") or an error directive (explained in "Error Directives"). Find the names of the employees who earn a salary in the range of 12000 to 15000. Because the aliases are not enclosed in double quotation marks, they are displayed in uppercase letters. The character $ can also appear inside plsql_identifier, but it has no special meaning there. A declaration allocates storage space for a value of a specified data type, and names the storage location so that you can reference it. I have a table in Oracle called orders which has the following fields: order_no, customer, and amount. You can reference identifiers declared in the packages STANDARD and DBMS_STANDARD without qualifying them with the package names, unless you have declared a local identifier with the same name (see "Scope and Visibility of Identifiers"). "searched_case_expression ::=" for the complete syntax. Character functions accept character input. It creates the output in XML. Because sal is an IN OUT parameter, the variable new_sal retains the assigned value after the procedure finishes running. Example 2-53 Searched CASE Expression with WHEN IS NULL. That question is answered by the clause just above the for clause inside the unpivot operator in the above query. The SYSTIMESTAMP function returns a TIMESTAMP value. After the area is computed, the result is displayed. A PLS_INTEGER literal whose value is the number of the source line on which the directive appears in the current PL/SQL unit. Syntax: DECODE( expression, search, result, search, result , default ) Parameters: After declaring a variable, you can assign a value to it in these ways: Use the assignment statement to assign it the value of an expression. Another example using the NVL function in Oracle/PLSQL is: This SQL statement would return the supplier_name field if the supplier_desc contained a null value. The wildcard character, *, represents an entire record. All databases that are not relational (or do For more information, see "Value Comparisons". This example uses a searched CASE expression to solve the problem in Example 2-51. Every database character set includes these basic characters: Latin letters: A through Z and a through z, Whitespace characters: space, tab, new line, and carriage return. Retrieving and Printing Post-Processed Source Text, Conditional Compilation Directive Restrictions. Making statements based on opinion; back them up with references or personal experience. These operators and functions can have table data as operands and arguments. Each numeric function returns a single value for each row that is evaluated. Using a simple case statement in a procedure, Using IF statements in Oracle when trying to return data, Add a column with a default value to an existing table in SQL Server. A final example using the NVL function in Oracle/PLSQL is: This SQL statement would return 0 if the commission field contained a null value. To do the tutorials and examples in this document, you must connect to Oracle Database Express Edition as the user HR. Suppose that you want to select the FIRST_NAME, LAST_NAME, and DEPARTMENT_NAME of every employee. These scripts simply queried that data dictionary and produced human readable SQL files of what the database design reality was at that particular time. Each datetime function returns a single value for each row that is evaluated. */, Divide-by-zero error: cannot divide 22 by 0, done BOOLEAN; -- Initial value is NULL by default, done := FALSE; -- Assign literal value, done != TRUE -- Compare to literal value, done := (counter > 500); -- Assign value of BOOLEAN expression, ELSIF a != b THEN -- yields NULL, not TRUE, (on_hand = 0) OR ((on_order / on_hand) < 5), "Variable Initialized to NULL by Default", "Searched CASE Expression with WHEN IS NULL", a INTEGER; -- Initialized to NULL by default, WHEN grade = 'F' OR attendance < min_days, THEN 'Poor (poor performance or bad attendance)', WHEN grade IS NULL THEN 'No grade assigned', PLSQL_CCFlags = 'Some_Flag:1, Some_Flag:2, PLSQL_CCFlags:99', Oracle Database PL/SQL Packages and Types Reference, $ERROR 'unsupported database release' $END, PLSQL_CCFLAGS = 'my_debug:FALSE, my_tracing:FALSE'. Alternatively, in SQLDeveloper, you can omit the ORDER BY clause and double-click the name of the column to sort. That's why we have specified DISTINCT clause above. You must qualify an identifier when it is not visible (see "Scope and Visibility of Identifiers"). Example 2-12 Selecting Data from Two Tables (Joining Two Tables). This practice minimizes invalidations caused by altering the package specification. The state_codes are presented on the header row, instead of a column. Here is an example of how you would combine the NOT Operator with the BETWEEN condition. Later assignments override earlier assignments. The simplest form of query has this syntax: The select_list specifies the columns from which the data is to be selected, and the source_list specifies the tables or views that have these columns. A delimiter is a character, or character combination, that has a special meaning in PL/SQL. * If selector has the value NULL, it cannot be matched by WHEN NULL, as this example shows. Example 4-46 Using the DECODE Function in a Query. Example 4-33 Converting Numbers to Characters Using a Format Template. Because later assignments override earlier assignments, the resulting value of $$Some_Flag is 2 and the resulting value of PLSQL_CCFLAGS is the value that it assigns to itself (99), not the value that the ALTER SESSION statement assigns to it ('Some_Flag:1, Some_Flag:2, PLSQL_CCFlags:99'). Error directives raise user-defined errors. In this example, the variable surname inherits the data type and size of the column employees.last_name, which has a NOT NULL constraint. Stored source text of PL/SQL units. For information about static expressions, see "Static Expressions". In the right frame of the Oracle SQLDeveloper window, in the Columns pane, a list of all columns of this table appears. oracleOracledbfORACLE Initial Values of Variables and Constants, Declaring Items using the %TYPE Attribute. my_pi := 3.14159265358979323846264338327950288420; my_e := 2.71828182845904523536028747135266249775; my_pi := 3.14159265358979323846264338327950288420d; my_e := 2.71828182845904523536028747135266249775d; Declaring Items using the %ROWTYPE Attribute, PLS_INTEGER and BINARY_INTEGER Data Types. If the connection succeeds, the Status indicator changes from blank to Success. The query in Example 4-30 uses the SYSTIMESTAMP function to display the current system time and date. In Example 2-57, the package my_debug defines the static constants debug and trace to control debugging and tracing in multiple PL/SQL units. The get_domain function returns the domain name from a URL string, assuming that the URL string has the " www " prefix immediately preceding the domain name, and the domain name is separated by dots on the left and right. The database character set defines which characters are classified as letters and digits. As the name suggests in this example we are going to see with the help of an example of how to drop a trigger that has been created and stored in the database. If your string does not fit on a source line and you do not want it to include a line-break character, then construct the string with the concatenation operator (||). The DECODE function can be used in the following versions of Oracle or PLSQL: Oracle 12c, Oracle 11g, Oracle 10g, Oracle 9i. It is easy for machines to parse and generate. Example 4-14 Sorting Selected Data by LAST_NAME. For the syntax of an expression, see "Expression". (The SQL function TO_CHAR returns the character equivalent of its argument. Employees who have changed jobs more than once have multiple rows in the JOB_HISTORY table, as the following query and its results show: The query in Example 4-26 uses the MONTHS_BETWEEN function to show how many months each employee held each of his or her previous jobs. Example 4-28 Displaying the Last Day of a Selected Month. Character values of data types CHAR, VARCHAR2, CLOB, and LONG. But, again, that is unknown, so the IF condition yields NULL and the sequence of statements is bypassed. The query in Example 4-7 tests for two conditionswhether the salary is at least 11000, and whether the commission percentage is not null. Each character function returns a single value for each row that is evaluated. For example: Question: Is it possible to use the NVL function with more than one column with the same function call? An example of a predefined identifier is the exception INVALID_NUMBER. Ensure that your temporary tablespace is large enough to handle them. The syntax is: If the identifier is declared in a PL/SQL unit on a remote database, you must reference it with its qualified remote name. The query in Example 2-7 selects data only for employees in department 90. Or you can use the reverse operation of pivot UNPIVOTto break up the columns to become rows, as is possible in Oracle Database 11g. You can rewrite it to use the ELSE condition of a CASE: Since web search for Oracle case tops to that link, I add here for case statement, though not answer to the question asked about case expression: Per Oracle docs: https://docs.oracle.com/cd/B10501_01/appdev.920/a96624/04_struc.htm. For example, this expression is true: If you set the initialization parameter NLS_COMP=ANSI, string comparisons use the collating sequence identified by the NLS_SORT initialization parameter. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Whether x equals y is unknown. In the right frame, click the tab Constraints. For example, the identifiers lastname and last_name are different. This section explains how to run queries in SQLDeveloper, by using the Worksheet. In this case, it is used in the file creation form. You cannot use the SQLCODE and SQLERRM functions in SQL statements. Note how the data is represented as rows of values: For each customer, the record shows the customer's home state and how many times the customer purchased something from the store. With SQL*Plus, you can use the SQL*Plus command DESCRIBE to view the properties of the columns of the EMPLOYEES table in the HR schema and the SQL statement SELECT to view the data. Example 2-23 Limiting Aggregate Functions to Rows that Satisfy a Condition. 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