Question

我目前正在尝试运行这段代码：

SELECT DISTINCT P.PlayerID
FROM Players as P, AllStar as A
WHERE P.PlayerID = A.PlayerID
GROUP BY P.PlayerID
HAVING COUNT(a.GamesPlayed) >= 8 // each GamesPlayed is always = 1

EXCEPT
SELECT DISTINCT P.PlayerID
FROM Players as P, HallOfFame as HOF
WHERE P.PlayerID = HOF.hofID OR P.Year BETWEEN 2010 AND 2017;

要找到所有参加过至少8场AllStar比赛的篮球运动员，不在名人堂，而且他们的最后几年都是在2010年之前。不幸的是，我目前的代码块并没有给我正确的权利。结果，但在我看来，我的逻辑检查在这里。有人可以帮我识别我在这里做错了吗？

非常感谢！

Answer 1

WHERE子句中的EXCEPT子句看起来不对：

WHERE P.PlayerID = HOF.hofID OR P.Year BETWEEN 2010 AND 2017;

我想你想要一个LEFT JOIN：

EXCEPT
SELECT DISTINCT P.PlayerID
FROM Players as P
LEFT JOIN  HallOfFame as HOF
ON P.PlayerID = HOF.hofID 
WHERE HOF.hofID IS NOT NULL OR P.Year BETWEEN 2010 AND 2017;

Answer 2

我不会想到使用EXCEPT解决这个问题。对我来说，这是一个带有WHERE过滤器的聚合查询：

SELECT P.PlayerID
FROM Players P JOIN
     AllStar A
     ON P.PlayerID = A.PlayerID
WHERE NOT EXISTS (SELECT 1 FROM HallOfFame HOF WHERE P.PlayerID = HOF.hofID)
GROUP BY P.PlayerID
HAVING COUNT(a.GamesPlayed) >= 8 AND
       MAX(P.Year) < 2010;

SQL EXCEPT子句及其行为

2 个答案: