Syntax:
SHOW [GLOBAL | SESSION] STATUS [LIKE 'pattern']

SHOW STATUS provides server status information. This information also
can be obtained using the mysqladmin extended-status command.
With a LIKE clause, the statement displays only rows for those
variables with names that match the pattern:

mysql> SHOW STATUS LIKE 'Key%';
+--------------------+----------+
| Variable_name      | Value    |
+--------------------+----------+
| Key_blocks_used    | 14955    |
| Key_read_requests  | 96854827 |
| Key_reads          | 162040   |
| Key_write_requests | 7589728  |
| Key_writes         | 3813196  |
+--------------------+----------+

The GLOBAL and SESSION options are new in MySQL 5.0.2. With the GLOBAL
modifier, SHOW STATUS displays the status values for all connections to
MySQL. With SESSION, it displays the status values for the current
connection. If no modifier is present, the default is SESSION. LOCAL is
a synonym for SESSION.

Some status variables have only a global value. For these, you get the
same value for both GLOBAL and SESSION.

Note: Before MySQL 5.0.2, SHOW STATUS returned global status values.
Because the default as of 5.0.2 is to return session values, this is
incompatible with previous versions. To issue a SHOW STATUS statement
that will retrieve global status values for all versions of MySQL,
write it like this:

SHOW /*!50002 GLOBAL */ STATUS;

URL: http://dev.mysql.com/doc/refman/5.0/en/show-status.html

