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

SHOW STATUS provides server status information. This information also
can be obtained using the mysqladmin extended-status command. The LIKE
clause, if present, indicates which variable names to match. The WHERE
clause can be given to select rows using more general conditions, as
discussed in http://dev.mysql.com/doc/refman/5.0/en/extended-show.html.
This statement does not require any privilege. It requires only the
ability to connect to the server.
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. The scope for each status
variable is listed at
http://dev.mysql.com/doc/refman/5.0/en/server-status-variables.html.

*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

