SHOW WARNINGS

SHOW WARNINGS 语句用于显示当前客户端连接中已执行语句的报错列表。与在 MySQL 中一样，sql_mode 极大地影响哪些语句会导致错误与警告。

语法图

ShowWarningsStmt

SHOW WARNINGS - 图1

1. ShowWarningsStmt ::=
2. "SHOW" "WARNINGS"

示例

1. CREATE TABLE t1 (a INT UNSIGNED);

1. Query OK, 0 rows affected (0.11 sec)

1. INSERT INTO t1 VALUES (0);

1. Query OK, 1 row affected (0.02 sec)

1. SELECT 1/a FROM t1;

1. +------+
2. | 1/a  |
3. +------+
4. | NULL |
5. +------+
6. 1 row in set, 1 warning (0.00 sec)

1. SHOW WARNINGS;

1. +---------+------+---------------+
2. | Level   | Code | Message       |
3. +---------+------+---------------+
4. | Warning | 1365 | Division by 0 |
5. +---------+------+---------------+
6. 1 row in set (0.00 sec)

1. INSERT INTO t1 VALUES (-1);

1. ERROR 1264 (22003): Out of range value for column 'a' at row 1

1. SELECT * FROM t1;

1. +------+
2. | a    |
3. +------+
4. |    0 |
5. +------+
6. 1 row in set (0.00 sec)

1. SET sql_mode='';

1. Query OK, 0 rows affected (0.00 sec)

1. INSERT INTO t1 VALUES (-1);

1. Query OK, 1 row affected, 1 warning (0.01 sec)

1. SHOW WARNINGS;

1. +---------+------+---------------------------+
2. | Level   | Code | Message                   |
3. +---------+------+---------------------------+
4. | Warning | 1690 | constant -1 overflows int |
5. +---------+------+---------------------------+
6. 1 row in set (0.00 sec)

1. SELECT * FROM t1;

1. +------+
2. | a    |
3. +------+
4. |    0 |
5. |    0 |
6. +------+
7. 2 rows in set (0.00 sec)

MySQL 兼容性

SHOW WARNINGS 语句与 MySQL 完全兼容。如发现任何兼容性差异，请尝试 TiDB 支持资源。

另请参阅