sql-statement-show-warnings.md

title	summary	aliases
SHOW WARNINGS | TiDB SQL Statement Reference	An overview of the usage of SHOW WARNINGS for the TiDB database.	/docs/dev/sql-statements/sql-statement-show-warnings/ /docs/dev/reference/sql/statements/show-warnings/

SHOW WARNINGS

This statement shows a list of warnings that occurred for previously executed statements in the current client connection. As in MySQL, the sql_mode impacts which statements will cause errors vs. warnings considerably.

Synopsis

ShowWarningsStmt:

Examples

mysql> CREATE TABLE t1 (a INT UNSIGNED);
Query OK, 0 rows affected (0.11 sec)

mysql> INSERT INTO t1 VALUES (0);
Query OK, 1 row affected (0.02 sec)

mysql> SELECT 1/a FROM t1;
+------+
| 1/a  |
+------+
| NULL |
+------+
1 row in set, 1 warning (0.00 sec)

mysql> SHOW WARNINGS;
+---------+------+---------------+
| Level   | Code | Message       |
+---------+------+---------------+
| Warning | 1365 | Division by 0 |
+---------+------+---------------+
1 row in set (0.00 sec)

mysql> INSERT INTO t1 VALUES (-1);
ERROR 1264 (22003): Out of range value for column 'a' at row 1
mysql> SELECT * FROM t1;
+------+
| a    |
+------+
|    0 |
+------+
1 row in set (0.00 sec)

mysql> SET sql_mode='';
Query OK, 0 rows affected (0.00 sec)

mysql> INSERT INTO t1 VALUES (-1);
Query OK, 1 row affected, 1 warning (0.01 sec)

mysql> SHOW WARNINGS;
+---------+------+---------------------------+
| Level   | Code | Message                   |
+---------+------+---------------------------+
| Warning | 1690 | constant -1 overflows int |
+---------+------+---------------------------+
1 row in set (0.00 sec)

mysql> SELECT * FROM t1;
+------+
| a    |
+------+
|    0 |
|    0 |
+------+
2 rows in set (0.00 sec)

MySQL compatibility

The SHOW WARNINGS statement in TiDB is fully compatible with MySQL. If you find any compatibility differences, report a bug.

See also

• SHOW ERRORS