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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.
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.
Oracle Database 23c extended CASE expressions in PL/SQL to support dangling predicates in simple CASE expression. These work like regular simple CASE expressions - you have a single selector. Each WHEN clause may contain a comparison condition and the right-hand side of the formula.
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.
Script Name Simple SQL CASE example; Description In this simple CASE expression, Oracle Database evaluates the first WHEN and returns the THEN if satisfied. It next considers the next WHEN condition. If none of the when conditions are met the ELSE is taken. Area SQL General; Contributor Mike Hichwa (Oracle) Created Tuesday February 23, 2016
15 Μαρ 2021 · WITH x AS ( SELECT level+1 a,level+2 b,level+3 c,level+4 d,level+5 e FROM dual CONNECT BY level <= 10) SELECT CASE a+b+c+d+e WHEN <30 THEN 'Below 30' WHEN <60 THEN 'Below 60' WHEN IS NULL THEN 'NULL' ELSE 'Above' END FROM x;
