SET [GLOBAL|SESSION]

SET [GLOBAL|SESSION] 语句用于在 SESSION 或 GLOBAL 的范围内，对某个 TiDB 的内置变量进行更改。需注意，对 GLOBAL 变量的更改不适用于已有连接或本地连接，这与 MySQL 类似。只有新会话才会反映值的变化。

语法图

SetStmt:

示例

mysql> SHOW GLOBAL VARIABLES LIKE 'sql_mode';
++-+
| Variable_name | Value                                                                                                                                     |
++-+
| sql_mode      | ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION |
++-+
1 row in set (0.00 sec)
mysql> SHOW SESSION VARIABLES LIKE 'sql_mode';
++-+
| Variable_name | Value                                                                                                                                     |
++-+
| sql_mode      | ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION |
++-+
1 row in set (0.00 sec)
mysql> SET GLOBAL sql_mode = 'STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER';
Query OK, 0 rows affected (0.03 sec)
mysql> SHOW GLOBAL VARIABLES LIKE 'sql_mode';
++--+
| Variable_name | Value                                   |
++--+
| sql_mode      | STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER |
++--+
1 row in set (0.00 sec)
mysql> SHOW SESSION VARIABLES LIKE 'sql_mode';
++-+
| Variable_name | Value                                                                                                                                     |
++-+
| sql_mode      | ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION |
++-+
1 row in set (0.00 sec)
mysql> SET SESSION sql_mode = 'STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER';
Query OK, 0 rows affected (0.01 sec)
mysql> SHOW SESSION VARIABLES LIKE 'sql_mode';
++--+
| Variable_name | Value                                   |
++--+
| sql_mode      | STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER |
++--+
1 row in set (0.00 sec)

MySQL 兼容性

SET [GLOBAL|SESSION] 语句与 MySQL 完全兼容。如有任何兼容性差异，请在 GitHub 上提交 issue。

另请参阅

• SHOW [GLOBAL|SESSION] VARIABLES