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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. For example, you can use the CASE expression in statements such as SELECT, UPDATE, or DELETE, and in clauses like SELECT, WHERE, HAVING, and ORDDER BY.
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 · You can use a case expression like this: The database processes the expression from top-to-bottom. It returns the value for the first when clause that is true. If none are true (the percentage is less than 50 or null), it returns the value in the else clause which is F.
Value Match (Simple) CASE Expression. The CASE expression is like a more flexible version of the DECODE function. The value match CASE expression, or simple CASE expression, compares the value of the expression (DEPTNO), with the list of comparison expressions (10 - 40).
Area SQL General. Contributor Mike Hichwa (Oracle) Created Tuesday February 23, 2016. Statement 1. select ename, case when sal >= 2900 then 'High' when sal > 1400 then 'Medium' else 'Low' end salary_scale. from scott.emp. 14 rows selected. Additional Information.
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.
2 Ιουν 2023 · The syntax of the SQL CASE expression is: CASE [expression] WHEN condition_1 THEN result_1 WHEN condition_2 THEN result_2 ... WHEN condition_n THEN result_n ELSE result END case_name. The CASE statement can be written in a few ways, so let’s take a look at these parameters. Parameters of the CASE Statement
