SHOW VARIABLES syntax
SHOW [{GLOBAL | SESSION}] VARIABLES [WHERE variable_name='xxx']
SHOW VARIABLES statement was added in version 2.0.1-beta to improve compatibility with 3rd party MySQL connectors and frameworks that automatically execute this statement. The WHERE option was added in version 2.1.1-beta.
In version 2.0.1-beta, it did nothing.
Starting from version 2.0.2-beta, it returns the current values of a few server-wide variables. Also, support for GLOBAL and SESSION clauses was added.
mysql> SHOW GLOBAL VARIABLES;
+----------------------+----------+
| Variable_name | Value |
+----------------------+----------+
| autocommit | 1 |
| collation_connection | libc_ci |
| query_log_format | sphinxql |
| log_level | info |
+----------------------+----------+
4 rows in set (0.00 sec)
Starting from 2.1.1-beta, support for WHERE variable_name clause was added, to help certain connectors.
