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 through the
SHOW ERRORSstatements. The
warning_countsystem variable indicates the number of errors, warnings, and notes. The
error_countsystem variable indicates the number of errors. Its value excludes warnings and notes.
SHOW SLAVE STATUSstatement output includes information about replication errors occurring on the slave side.