Detect if value is number in MySQL

This should work in most cases.

SELECT * FROM myTable WHERE concat('',col1 * 1) = col1

It doesn't work for non-standard numbers like

• 1e4
• 1.2e5
• 123. (trailing decimal)

You can use Regular Expression too... it would be like:

SELECT * FROM myTable WHERE col1 REGEXP '^[0-9]+$';

Reference: http://dev.mysql.com/doc/refman/5.1/en/regexp.html