sql-statement-show-warnings.md

title	summary	aliases
SHOW WARNINGS	TiDB 数据库中 SHOW WARNINGS 的使用概况。	/docs-cn/dev/sql-statements/sql-statement-show-warnings/ /docs-cn/dev/reference/sql/statements/show-warnings/

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"

示例

{{< copyable "sql" >}}

CREATE TABLE t1 (a INT UNSIGNED);

Query OK, 0 rows affected (0.11 sec)

{{< copyable "sql" >}}

INSERT INTO t1 VALUES (0);

Query OK, 1 row affected (0.02 sec)

{{< copyable "sql" >}}

SELECT 1/a FROM t1;

+------+
| 1/a  |
+------+
| NULL |
+------+
1 row in set, 1 warning (0.00 sec)

{{< copyable "sql" >}}

SHOW WARNINGS;

+---------+------+---------------+
| Level   | Code | Message       |
+---------+------+---------------+
| Warning | 1365 | Division by 0 |
+---------+------+---------------+
1 row in set (0.00 sec)

{{< copyable "sql" >}}

INSERT INTO t1 VALUES (-1);

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

{{< copyable "sql" >}}

SELECT * FROM t1;

+------+
| a    |
+------+
|    0 |
+------+
1 row in set (0.00 sec)

{{< copyable "sql" >}}

SET sql_mode='';

Query OK, 0 rows affected (0.00 sec)

{{< copyable "sql" >}}

INSERT INTO t1 VALUES (-1);

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

{{< copyable "sql" >}}

SHOW WARNINGS;

+---------+------+---------------------------+
| Level   | Code | Message                   |
+---------+------+---------------------------+
| Warning | 1690 | constant -1 overflows int |
+---------+------+---------------------------+
1 row in set (0.00 sec)

{{< copyable "sql" >}}

SELECT * FROM t1;

+------+
| a    |
+------+
|    0 |
|    0 |
+------+
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

• SHOW ERRORS