I have a table of Users on a MySQL database, which includes a field, BirthDate.

I would like to be able to:

1. Calculate the User's age, based on the BirthDate, to return in a query, and
2. Filter by that calculated age (i.e.: Find everyone from 18-25).

I have found various examples of returning the age in a query, but I haven't found the best way to filter by age, age range, etc.

A HAVING clause should work. The following is an expansion of the PET tutorial example in the msyql manual (untested but should work) -

SELECT name, birth, CURDATE(),
(YEAR(CURDATE())-YEAR(birth)) - (RIGHT(CURDATE(),5)<RIGHT(birth,5))
AS age
FROM pet
HAVING age >= 18 AND age <= 25

You could also put the age calculation into a WHERE clause with the comparisons.

Thanks. I originally tried it using a WHERE clause on the age alias, and it didn't work. I tried your example with the HAVING clause, and it did the trick.

do you undestand what this is doing? --
if not, i would suggest that you re-write it using a CASE expression, because it won't work in any other database written like that