mysql - mysql、サブクエリカウント順

Question

私はこれをやろうとしています:

SELECT 
    id, user_id, roi, 
    (select count(id) from main_ub U where U.user_id=W.user_id and U.cons > 0) as COUNT 
FROM 
    main_stats W 
WHERE 
    week=43 and year=2013 and votes > 2 and COUNT >= 20
ORDER BY 
    roi desc
LIMIT 1

しかし、私は常にこのエラーが発生します:

#1054 - Unknown column 'COUNT' in 'where clause'

WHERE 句で内部選択を使用することは可能ですか?

Answer 1

SELECT * FROM 

(SELECT 
    id, user_id, roi, 
    (select count(id) from main_ub U where U.user_id=W.user_id and U.cons > 0) as COUNT 
FROM 
    main_stats W 
WHERE 
    week=43 and year=2013 and votes > 2) res 

WHERE res.COUNT >= 20
ORDER BY 
    res.roi desc
LIMIT 1