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 C.2, “Types of Error Values”. These errors are returned from the server side; see Section C.3, “Server Error Codes and Messages”.
Errors can occur on the client side, usually involving problems communicating with the server; see Section C.4, “Client Error Codes and Messages”.
SQL statement warning and error information is available through the
SHOW WARNINGSandSHOW ERRORSstatements. Thewarning_countanderror_countsystem variables provide counts of the number of warnings and errors.SHOW SLAVE STATUSstatement output includes information about replication errors occurring on the slave side.SHOW ENGINE INNODB STATUSstatement output includes information about the most recent foreign key error if aCREATE TABLEstatement for anInnoDBtable fails.The perror program provides information from the command line about error numbers. See Section 4.8.1, “perror — Explain Error Codes”.
Descriptions of server and client errors are provided later in
this Appendix. For information about errors related to
InnoDB, see
Section 13.6.13, “InnoDB Error Handling”.