There are several sources of error information in MySQL:
Each SQL statement executed results in an error code, an SQLSTATE value, and an error message, as described in Section B.2, “Types of Error Values”. These errors are returned from the server side; see Section B.3, “Server Error Codes and Messages”.
Errors can occur on the client side, usually involving problems communicating with the server; see Section B.4, “Client Error Codes and Messages”.
SQL statement warning and error information is available via the
SHOW WARNINGS and
SHOW ERRORS statements. The
error_count system variables provide counts of the number of warnings and errors.
SHOW SLAVE STATUS statement output includes information about replication errors occurring on the slave side.
Descriptions of server and client errors are provided later in this Appendix. For information about errors related to
InnoDB, see Section 13.6.12, “
InnoDB Error Handling”.