<p>MySQL error 1643 (ER_SIGNAL_NOT_FOUND) occurs when a SIGNAL or RESIGNAL statement references a condition name that has not been declared in the current stored program.</p>
<p>MySQL Error 1643: ER_SIGNAL_NOT_FOUND means the SIGNAL or RESIGNAL statement tried to raise a condition that was never declared inside the stored procedure or trigger. Declare the condition or use SQLSTATE directly to fix the issue.</p>
Unhandled user-defined not found condition
MySQL raises error 1643 when a SIGNAL or RESIGNAL statement tries to reference a condition name that does not exist in the current compound statement or block. The error message is: Unhandled user-defined not found condition.
The problem is runtime only. Your procedure compiles, but when execution reaches the offending SIGNAL or RESIGNAL, MySQL cannot find the referenced condition and aborts.
Unhandled runtime errors interrupt transaction flow, roll back work, and confuse end users. Left unfixed, ER_SIGNAL_NOT_FOUND can hide deeper business-logic bugs and complicate error-handling strategies.
Most cases involve misspelled condition names, conditions declared in a different scope, or the use of RESIGNAL without a preceding HANDLER. Migrating code between MySQL versions or copy-pasting examples can also introduce the issue.
Declare the missing condition with DECLARE … CONDITION before using SIGNAL/RESIGNAL, or reference the error via SQLSTATE '45000' directly. Make sure the declaration is in the same block scope.
In stored procedures, the error appears when jumping from nested blocks. In AFTER TRIGGERs, referencing a condition from a parent routine causes failure. Align condition scope or convert to SQLSTATE.
Always place DECLARE CONDITION statements at the top of each BEGIN … END block, use clear naming conventions, and unit-test stored programs. Galaxy’s inline error linting flags undeclared conditions before execution.
Similar runtime issues include 1339 Handler already declared and 1172 Result consisted of more than one row. They stem from handler, cursor, and result-set mismanagement and follow similar debugging steps.
The SIGNAL statement references a condition identifier that differs in spelling or case from the one declared earlier.
No DECLARE CONDITION statement exists in the current BEGIN … END block, so the name cannot be resolved at runtime.
The condition was declared in an outer block, but SIGNAL runs inside an inner block that does not inherit the declaration.
A RESIGNAL statement executes even though no corresponding HANDLER captured the error, leaving MySQL without a valid condition context.
Migrating stored programs between servers or versions can drop or rename condition declarations, triggering the error.
Occurs when a duplicate HANDLER is defined in the same scope. Remove or rename one handler.
Raised when a subquery returns multiple rows in a context expecting one. Rewrite the query or add LIMIT 1.
Appears when SQL security characteristics are missing. Add the required DETERMINISTIC or NO SQL clauses.
Yes, if you use a named condition in SIGNAL or RESIGNAL, declare it first in the same block. Otherwise reference the SQLSTATE directly.
No. DECLARE CONDITION is scoped to the block. Declare it in each procedure or use SQLSTATE literals.
ER_SIGNAL_NOT_FOUND exists from MySQL 5.5 onward. The causes are the same across versions, but newer releases provide clearer diagnostics.
Galaxy’s real-time parser checks stored program blocks and flags any SIGNAL statements lacking a matching DECLARE CONDITION, preventing runtime failures.
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