MySQL in a Nutshell, 2nd Edition

Name

UNCOMPRESSED_LENGTH()

Synopsis

UNCOMPRESSED_LENGTH(string)

This function returns the number of characters contained in the given compressed string before it was compressed. You can compress strings using the COMPRESS() function. This function is available as of version 4.1 of MySQL. Here is an example:

SELECT UNCOMPRESSED_LENGTH(COMPRESS(essay))
FROM student_applications
WHERE applicant_id = '1748';