-3
下面音樂庫DB：在哪裏clausule返回第一個子查詢？
而下面的查詢：
SELECT CDNumber
FROM CD
WHERE CDNumber NOT IN
(SELECT T2.CDNumber
FROM Track AS T1 JOIN Singer AS S1 ON T1.PerformanceCode = S1.PerformanceCode
JOIN Singer AS S2 ON T1.PerformanceCode = S2.PerformanceCode
WHERE S1.SingerName <> S2.SingerName)
AND CDNumber IN
(SELECT T2.CDNumber
FROM Track AS T2 JOIN Recording AS R ON T2.PerformanceCode = R.Performance
WHERE R.Year < CD.Year
GROUP BY CDNumber
HAVING count(*) >= 3)
問：是否在第一子查詢的WHERE子句返回CD的號碼，所有的歌曲都是由一個歌手？（YES/NO）我怎麼知道這個？