Filtering on an alias in mysql

Question

Why doesn\'t the following query work? Mysql complains about z - can\'t I use an alias in the WHERE clause?

SELECT x + y AS z, t.*  FROM t
WHERE 
x = 1 and
z         


        

Answer 1

Use having clause:

SELECT (x + y) AS z, t.*  FROM t
WHERE 
x = 1 
having z=2