Error 1339 occurs when a CASE statement inside a stored program evaluates to a value that matches none of its WHEN clauses and the statement lacks an ELSE branch.
MySQL Error 1339: ER_SP_CASE_NOT_FOUND appears when a CASE expression in a stored procedure, trigger, or function evaluates to a value that matches no WHEN clause and no ELSE clause exists. Add a defensive ELSE or ensure every possible value is covered to resolve the issue.
Case not found for CASE statement
MySQL raises error 1339 with the message "Case not found for CASE statement" during stored program execution when a CASE expression evaluates to a value that is not handled by any WHEN branch and no ELSE branch is supplied.
The error aborts the current stored procedure, function, or trigger, returning SQLSTATE 20000, which signals an unhandled user-defined condition. Addressing it quickly prevents partial data changes and confusing client-side failures.
The engine checks CASE branches only at runtime. You might compile a procedure successfully, but the first call that passes an unexpected value will raise ER_SP_CASE_NOT_FOUND.
Typical contexts include complex control-flow logic, dynamic handlers, and migration scripts where enumerations have grown without matching code updates.
Missing ELSE clauses are the primary trigger. If your CASE statement lists explicit WHEN values but forgets a default path, any unlisted value will cause error 1339.
Logic drift also contributes: new enum strings, status codes, or input parameters get added to tables, but the stored routine’s CASE logic is not updated accordingly.
Add an ELSE branch that returns a safe default or raises a custom error. Alternatively, enumerate all valid WHEN values or validate inputs before the CASE statement.
After code changes, rerun unit tests or call the procedure with edge cases to confirm the error no longer appears.
In status-driven workflows, new order states (e.g., "RETURNED") often slip past CASE logic. Extending the WHEN list removes the error.
For user-supplied parameters, defending with an ELSE that SIGNALs an informative error keeps bugs obvious while avoiding silent data issues.
Always include an ELSE branch that either handles unknown cases gracefully or signals a descriptive error.
Add CHECK constraints or BEFORE triggers to validate acceptable values, and keep stored program logic under version control with automated tests.
Errors 1329, 1330, and 1644 also involve stored program SIGNAL/RESIGNAL handling. They differ in that they relate to RESIGNAL misuse, undefined handlers, or explicit SIGNAL statements with malformed SQLSTATE codes.
Omitting a fallback ELSE means any unmatched value triggers ER_SP_CASE_NOT_FOUND.
Tables or application code introduce new values that the stored routine’s CASE logic does not yet cover.
Procedures receiving unchecked parameters may encounter values not represented in the WHEN clauses.
Developers removing or reordering WHEN blocks might inadvertently drop coverage for certain paths.
Occurs when a GOTO statement jumps out of a handler; fixed by restructuring flow control.
Raised when creating a trigger that already exists; drop or rename the existing trigger first.
Generated by explicit SIGNAL statements; review SQLSTATE codes and message text for correctness.
Yes. An ELSE guarantees the routine handles unexpected values gracefully, preventing runtime errors and making maintenance easier.
You can, but silently ignoring data often masks bugs. Better practice is to SIGNAL a descriptive error for easier debugging.
No. The error is specific to stored programs (procedures, functions, triggers). A standalone SELECT returns NULL when no WHEN matches.
Galaxy’s AI copilot highlights missing ELSE branches during code review and lets teams endorse corrected queries, ensuring consistent, error-free stored routines.
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