sql - 删除除前 10 行之外的所有行

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)

关于为什么这会删除所有行的任何建议？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。这些列真的具有相同的值吗？

那么应该是

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

编辑：

尝试这个

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，但您的 select 子句应该引用 highscore_id，而不是 highscore。

Answer 3

尝试这个：

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

---

样本数据：

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

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

询问：

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

select * from beatles;

之前的删除：

NAME
brian
george
george martin
john
paul
pete
ringo

删除后：

NAME
brian
george
george martin
john

现场测试：http ://www.sqlfiddle.com/#!3/0adcf/6

Answer 4

我的第一个猜测是“SELECT TOP 10 highScore FROM Scores WHERE难度= 1 ORDER BY HighScore DESC”可能返回空值。

我的第二个猜测是“highscore_id”与“highscore”不同，因此没有重叠（也没有任何内容被删除）。

绝对要仔细检查您的子查询，并确保它返回您期望的键！