Table of Contents for

MySQL in a Nutshell, 2nd Edition

Use this statement to display error messages. The results are only for the previous statement that has been executed. To see the number of error messages generated by an SQL statement, use COUNT(*). To limit the number of error messages displayed, use the LIMIT clause. An offset can be given along with the count to specify a starting point for displaying error messages.

This statement is available as of version 4.1 of MySQL. It will not display warnings or notes—just error messages. Use SHOW WARNINGS to get all three types of messages.

Here are a couple of examples of this statement, which were entered after an INSERT statement was entered and encountered a problem:

SHOW COUNT(*) ERRORS;

+-----------------------+
| @@session.error_count |
+-----------------------+
|                     1 | 
+-----------------------+

SHOW ERRORS;

+-------+------+-------------------------------------------------+
| Level | Code | Message                                         |
+-------+------+-------------------------------------------------+
| Error | 1136 | Column count doesn't match value count at row 2 | 
+-------+------+-------------------------------------------------+

The first statement returns the number of error messages generated by the INSERT statement. Notice that the results are stored in the session variable error_count, which is updated by each statement issued in the session. The second statement displays the error messages. This statement is perhaps more meaningful when used with an API program in which you would like to capture the error messages for a specific purpose or analysis.