系统表介绍
user_variables_by_thread 用以展示用户定义的变量
| 列名 | 含义 |
|---|---|
| THREAD_ID | 线程编号 |
| VARIABLE_NAME | 变量名 |
| VARIABLE_VALUE | 变量值 |
实例
- 设置用户变量 ```sql
mysql> set @aaa =20 ; Query OK, 0 rows affected (0.00 sec)
- 查看变量
```sql
mysql> select *from user_variables_by_thread ;
+-----------+---------------+----------------+
| THREAD_ID | VARIABLE_NAME | VARIABLE_VALUE |
+-----------+---------------+----------------+
| 364 | aaa | 20 |
+-----------+---------------+----------------+
1 row in set (0.01 sec)