# 查看 SQL 模式

__*SQL 模式*__
__*SQL_MODE*__

+ 显示当前的 SQL 模式:
  + `select @@global.sql_mode;`
  + `select @@session.sql_mode;`
  + `select @@sql_mode;`
+ 默认 SQL 模式:
```8
mysql> select substring_index(@@sql_mode,',',4);
+---------------------------------------------------------------------+
| substring_index(@@sql_mode,',',4)                                   |
+---------------------------------------------------------------------+
| ONLY_FULL_GROUP_BY,~!@STRICT_TRANS_TABLES@!~,NO_ZERO_IN_DATE,NO_ZERO_DATE |
+---------------------------------------------------------------------+
1 row in set (0.01 sec)

mysql> select substring_index(@@sql_mode,',',-4);
+------------------------------------------------------------------------------------+
| substring_index(@@sql_mode,',',-4)                                                 |
+------------------------------------------------------------------------------------+
| NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION |
+------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
```
--------------------------------------------------------------------------------------

STRICT_TRANS_TABLES 的存在意味着 TiDB 默认处于严格模式。

稍后我们将讨论严格模式。