select with MD5 + CONCAT using where

Question

Where problem ? select work fine.. when check in where - give error Unknown column 'confirm' in 'where clause'

 SELECT 
    users_id, MD5(CONCAT(users_pass, users_email)) AS confirm
FROM
    (users_items) 
WHERE users_active = 0 
    AND confirm = '39a5eccb97f63a2bb649ddd95c5a3ba7' 
LIMIT 1 

Answer 1

因为确认是一个alias.

您不能在同一级别的查询中使用alias该where子句.

你必须做

where xxx
and MD5(CONCAT(users_pass, users_email)) = '39a5eccb97f63a2bb649ddd95c5a3ba7'

或者,如Vatev所述,您可以在HAVING子句中使用别名.但是使用一个HAVING条款可能会对性能产生影响.

导致查询过滤器(例如,尝试使用索引)和HAVING子句过滤这些过滤数据的原因.

where xxx
HAVING confirm = '39a5eccb97f63a2bb649ddd95c5a3ba7'