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Oracle CASE expression allows you to add if-else logic to SQL statements without having to call a procedure. The CASE expression evaluates a list of conditions and returns one of the multiple possible results. You can use a CASE expression in any statement or clause that accepts a valid expression.
In a simple CASE expression, Oracle Database searches for the first WHEN... THEN pair for which expr is equal to comparison_expr and returns return_expr. If none of the WHEN... THEN pairs meet this condition, and an ELSE clause exists, then Oracle returns else_expr. Otherwise, Oracle returns null.
You can rewrite it to use the ELSE condition of a CASE: SELECT status, CASE status WHEN 'i' THEN 'Inactive' WHEN 't' THEN 'Terminated' ELSE 'Active' END AS StatusText FROM stage.tst
This Oracle tutorial explains how to use the Oracle / PLSQL CASE statement with syntax and examples. The Oracle / PLSQL CASE statement has the functionality of an IF-THEN-ELSE statement. Starting in Oracle 9i, you can use the CASE statement within a SQL statement.
7 Δεκ 2023 · How to use CASE for IF-THEN logic in SQL SELECT. If you want to see the grade for each exam, select the case expression like a regular column: It’s a good idea to give the expression an alias. This is particularly important if the case is in a subquery.
Let’s examine the syntax of the simple CASE statement in detail: 1) selector. The selector is an expression that is evaluated once. The result of the selector is used to select one of the several alternatives e.g., selector_value_1 and selector_value_2. 2) WHEN selector_value THEN statements.
The CASE statement evaluates a single expression and compares it against several potential values, or evaluates multiple Boolean expressions and chooses the first one that is TRUE. Syntax. searched_case_statement ::=. [ <<label_name>> ] CASE { WHEN boolean_expression THEN {statement;} ...
