information_schema.tables+concat()实现命令拼接：

1concat()的作用：

可以实现拼接命令

mysql> select user,host from mysql.user;
+---------------+---------------+
| user          | host          |
+---------------+---------------+
| root          | %             |
| tyjs09        | %             |
| zhihu         | 10.0.0.%      |
| root          | 106.13.186.56 |
| mysql.session | localhost     |
| mysql.sys     | localhost     |
+---------------+---------------+
6 rows in set (0.01 sec)

mysql> select concat(user,"@",host) from mysql.user;
+-------------------------+
| concat(user,"@",host)   |
+-------------------------+
| root@%                  |
| tyjs09@%                |
| zhihu@10.0.0.%          |
| root@106.13.186.56      |
| mysql.session@localhost |
| mysql.sys@localhost     |
+-------------------------+
6 rows in set (0.00 sec)

mysql>