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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. Oracle CASE expression has two formats: the simple CASE expression and the searched CASE expression. Both formats support an optional ELSE clause.
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.
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).
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.
Oracle Data Warehousing Guide for examples using various forms of the CASE expression. Simple CASE Example For each customer in the sample oe.customers table, the following statement lists the credit limit as "Low" if it equals $100, "High" if it equals $5000, and "Medium" if it equals anything else.
Description. 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. Syntax. The syntax for the CASE statement in Oracle/PLSQL is: CASE [ expression ] WHEN condition_1 THEN result_1. WHEN condition_2 THEN result_2. ...
A WHEN clause can return the result of another CASE expression. This checks if the row is for a genuine result first. If it is, it returns the result of the grading CASE expression. It also has separate CASE expressions to see if a result is for a test exam or student, concatenating their output.
