EC
3143
MySQLERRORNotableStored RoutinesHIGH confidence

CASE statement has no matching WHEN clause and no ELSE

Production Risk

Medium — runtime error in stored procedures can abort a transaction.

What this means

A CASE statement in a stored procedure was executed but none of the WHEN conditions matched the operand, and no ELSE clause was provided to handle unmatched cases.

Why it happens
  1. 1CASE statement missing an ELSE branch.
  2. 2The CASE operand value is NULL or an unexpected value not covered by any WHEN clause.
How to reproduce
trigger — this will error
trigger — this will error
CREATE PROCEDURE test_case(IN v INT)
BEGIN
  CASE v
    WHEN 1 THEN SELECT 'one';
    WHEN 2 THEN SELECT 'two';
  END CASE;
END;

expected output

ERROR 3143 (20000): Case not found for CASE statement

Fix

Add an ELSE clause

Add an ELSE clause
CASE v
  WHEN 1 THEN SELECT 'one';
  WHEN 2 THEN SELECT 'two';
  ELSE SELECT 'other';
END CASE;

Why this works

ELSE handles all values not matched by WHEN clauses, preventing the error.

What not to do

✕

Sources
Official documentation ↗

MySQL 8.0 — 3143 ER_SP_CASE_NOT_FOUND

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