Question

我有以下SQL语句，它似乎正在删除所选表中的每一行。它应该做的是删除除了难度级别等于1的前10名之外的所有内容。

DELETE FROM Scores
WHERE Highscore_ID 
NOT IN (SELECT TOP 10 highScore FROM Scores WHERE difficulty = 1 ORDER BY HighScore DESC)

有关为什么会删除所有行的任何建议？在运行子查询时，它会选择正确的行，但是，在删除时，它似乎想要删除每一行。

Answer 1

您将Hichscore_Id与列highScore进行比较。这些列是否真的具有相同的值？

那应该是

DELETE FROM Scores 
WHERE Highscore_ID NOT IN
          (SELECT TOP 10 HighScore_ID 
           FROM Scores 
           WHERE difficulty = 1 
           ORDER BY HighScore DESC);

编辑：

试试这个

DELETE FROM Scores
JOIN (SELECT ROW_NUMBER() OVER (ORDER BY highscore) AS your_row, * 
      FROM Scores 
      WHERE difficulty = 1 
      ORDER BY HighScore DESC) AS score2 ON score2.HighScore_ID = Scores.HighScore_ID
WHERE Scores.difficulty = 1 AND score2.your_row>10

Answer 2

不知道这是拼写错误还是真正的错误，但你的select子句应该引用highscore_id，而不是高分。

Answer 3

试试这个：

with a as
(
select ROW_NUMBER() over(order by name) as ordinal, * from test
)
delete from a where a.ordinal > 10;

相关：http://www.ienablemuch.com/2012/03/possible-in-sql-server-deleting-any-row.html

示例数据：

CREATE TABLE [beatles]
    ([name] varchar(14));

INSERT INTO [beatles]
    ([name])
VALUES
    ('john'),
    ('paul'),
    ('george'),
    ('ringo'),
    ('pete'),
    ('brian'),
    ('george martin');

查询：

with a as
(
  select *, row_number() over(order by name) ordinal
  from beatles
)
delete from a
where ordinal > 4;

select * from beatles;

先前删除：

NAME
brian
george
george martin
john
paul
pete
ringo

删除后：

NAME
brian
george
george martin
john

实时测试：http://www.sqlfiddle.com/#!3/0adcf/6

Answer 4

我的第一个猜测是＆＃34; SELECT TOP 10 highScore FROM得分WHERE难度= 1 ORDER BY HighScore DESC＆＃34;可能会返回null。

我的第二个猜测是＆＃34; highscore_id＆＃34;与＆＃34; highscore＆＃34;不同，所以没有重叠（没有删除任何内容）。

绝对仔细检查您的子查询，并确保它返回您期望的密钥！

删除除前10行之外的所有行

4 个答案: