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MySQL error code

MySQL error 1646

MySQL server error 1646 is ER_SIGNAL_BAD_CONDITION_TYPE, reported with SQLSTATE HY000.

SIGNAL/RESIGNAL can only use a CONDITION defined with SQLSTATE
Error1646
NameER_SIGNAL_BAD_CONDITION_TYPE
SQLSTATEHY000
GroupServer errors

Source: MySQL 8.4 Error Reference