mysql - 无法在语句中使用多个 not

Question

我正在寻找练习和比赛表中不存在的条目，但是我无法使用第二个 not in 语句。还有其他方法可以做到这一点吗？

 select VenueID from Venue
 where VenueID not in (select VenueID from Practice)
 and not in (select VenueId from Game)

Answer 1

您需要重复NOT IN语句，包括列名称:

SELECT VenueID
FROM Venue
WHERE VenueID NOT IN (SELECT VenueID FROM Practice) AND
      VenueID NOT IN (SELECT VenueId FROM Game)
       ^^^ you omitted the second column name

使用 NOT IN 的一种替代方法是执行两次左连接:

SELECT VenueID
FROM Venue t1
LEFT JOIN Practice t2
    ON t1.VenueID = t2.VenueID
LEFT JOIN Game t3
    ON t1.VenueID = t3.VenueID
WHERE t2.VenueID IS NULL AND
      t3.VenueID IS NULL