MySQL-specific: $wgSQLMode
Value for the MySQL sql_mode parameter
Introduced in version:1.17.0 (r68558)
Removed in version:still in use
Allowed values:(string) or null
Default value:''

Details edit

If this setting is not null, the MySQL server is sent the SQL query SET sql_mode = "$wgSQLMode". See the MySQL documentation for more details.

The default is null, which means that the query to set sql_mode is not issued. This can be used to skip the setting for performance reasons and assume the database admin (DBA) has done their best job.