mysql - 需要帮助使用 SQL 编写查询，除了

Question

我正在编写一个查询，该查询将显示慈善机构尚未捐赠的内容。这是到目前为止我的脚本:

SELECT c.Name
FROM CHARITY c INNER JOIN
     DONATION d
     ON c.CharityID = d.DonationID
EXCEPT
select C.CharityID, donationID
from charity c join
     DONATION d
     on c.CharityID = d.DonationID
ORDER BY d.DonationID asc

我的输出应说明:

name                        DonationID
------                       ------
St. Francis Home             NULL
Salvation Army               Null
.....
.....

但我得到:

"Msg 205, Level 16, State 1, Line 1 All queries combined using a UNION, INTERSECT or EXCEPT operator must have an equal number of expressions in their target lists."

Answer 1

左连接和where怎么样:

SELECT c.Name
FROM CHARITY c LEFT JOIN
     DONATION d
     ON c.CharityID = d.DonationID
WHERE d.DonationID IS NULL;

我还要指出，将“CharityID”连接到“DonationID”的连接看起来非常可疑。