SHOW QUERIES

mysql> SHOW QUERIES;

+------+--------------+----------+-----------------+
| id   | query        | protocol | host            |
+--------------------------+-----------------------+
|    6 | select       | http     | 127.0.0.1:41128 |
|    4 | show queries | mysql    | 127.0.0.1:56672 |
+------+--------------+----------+-----------------+
2 rows in set (0.61 sec)

See also SHOW THREADS if you want to know what's going on from the threads angle of view.

SHOW WARNINGS statement can be used to retrieve the warning produced by the latest query. The error message will be returned along with the query itself:

mysql> SELECT * FROM test1 WHERE MATCH('@@title hello') \G
ERROR 1064 (42000): index test1: syntax error, unexpected TOK_FIELDLIMIT
near '@title hello'
mysql> SELECT * FROM test1 WHERE MATCH('@title -hello') \G
ERROR 1064 (42000): index test1: query is non-computable (single NOT operator)
mysql> SELECT * FROM test1 WHERE MATCH('"test doc"/3') \G
*************************** 1\. row ***************************
        id: 4
    weight: 2500
  group_id: 2
date_added: 1231721236
1 row in set, 1 warning (0.00 sec)
mysql> SHOW WARNINGS \G
*************************** 1\. row ***************************
  Level: warning
   Code: 1000
Message: quorum threshold too high (words=2, thresh=3); replacing quorum operator
         with AND operator
1 row in set (0.00 sec)

SHOW [{GLOBAL | SESSION}] VARIABLES LIKE 'pattern'

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      |
| max_allowed_packet       | 134217728 |
| character_set_client     | utf8      |
| character_set_connection | utf8      |
| grouping_in_utc          | 0         |
| last_insert_id           | 123, 200  |
+--------------------------+-----------+
9 rows in set (0.00 sec)

mysql> show variables like '%log%';
+------------------+----------+
| Variable_name    | Value    |
+------------------+----------+
| query_log_format | sphinxql |
| log_level        | info     |
+------------------+----------+
2 rows in set (0.00 sec)

mysql> show session variables like 'autocommit';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| autocommit    | 0     |
+---------------+-------+
1 row in set (0.00 sec)