How Can I Determine if a Value is an Integer in MySQL?

Determining Integer Values in MySQL

In MySQL, there are mechanisms to convert values into integers using functions like Cast() and Convert(). However, is there a method to directly ascertain whether a value is already an integer? This article explores a solution.

Solution Using REGEXP Operator (For String Values)

One effective approach for checking if a string value is an integer is to employ the REGEXP operator along with a regular expression. This expression matches the string with the following pattern:

^-?[0-9]+$

This pattern checks for a value that begins with a possible negative sign (-) followed by one or more digits (0-9). By applying the REGEXP operator as follows, you can retrieve all rows where the field matches this integer pattern:

SELECT field
FROM table
WHERE field REGEXP '^-?[0-9]+$';

This query efficiently identifies integer values within string data.

Solution Using Numeric Comparison (For Numeric Values)

If the field in question is numeric, you can leverage the ceil() function to compare its integer equivalent to the original value. If the two values are equal, this indicates that the field is an integer:

SELECT field
FROM table
WHERE ceil(field) = field;

This method is efficient for identifying integers in numeric fields. By applying either of these techniques, you can effectively determine whether a value is an integer in MySQL.

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