mysql> select count(1) ‘连接数‘,host_db.host ‘客户端‘ from ( select substring_index(host,‘:‘,1) as "host" from processlist ) host_db group by host_db.host;
+------+---------------+
| 连接数 | 客户端          |
+------+---------------+
|    3 | 172.16.91.237 |
|    3 | 172.16.91.249 |
|  186 | bogon         |
|   12 | localhost     |
+------+---------------+
4 rows in set

mysql> select count(1) ‘连接数‘,db ‘数据库‘ from processlist group by db;
+------+--------------------+
| 连接数 | 数据库               |
+------+--------------------+
|    1 | NULL               |
|    3 | bpm                |
|    3 | bpm_ys             |
|    3 | epm                |
|    2 | information_schema |
|  119 | perform2           |
|    5 | pms                |
|   39 | portal             |
|   29 | security_ys        |
+------+--------------------+
9 rows in set