Question

我有一张桌子和同桌的备份。在备份后，在主表中插入了一些数据。现在我想从主表中删除数据。怎么实现呢？让我们说桌子是＃Book;＆＃39;列为AuthorID，BookName，BookID。备份了BookMap＆＃39;表和插入的新数据。现在想要删除这些数据。

注意：我这里没有主键。

Answer 1

如果您希望backup_BookMap看起来像truncate table bookmap; insert into bookmap( . . .) select . . . from backup_bookmap;，那么您可能会考虑：

{{1}}

Answer 2

如果我理解正确，您要删除已插入备份表的非备份表中的数据：

DELETE nonbackup
FROM BookMap as nonbackup
WHERE nonbackup.BookID IN
(
    SELECT BookID
    FROM BookMapBackup as backup
)

Answer 3

尝试这样，

DELETE B FROM bookmark B INNER JOIN 
(
SELECT *FROM (
select *From bookmark
except
select *From bookmarkbackup)T
)T1 ON T1.AuthorID=B.AuthorID
AND T1.BookName=B.BookName
AND T1.BookID=B.BookID

Answer 4

以下是您可以测试的内容：

DECLARE @book table
(
    AuthorID varchar,
    BookName varchar(255),
    BookID int
);

DECLARE @backupBook table
(
    AuthorID varchar,
    BookName varchar(255),
    BookID int
);

insert into @book values(1, 'book1', 1 )
insert into @book values(2, 'book2', 2 )
insert into @book values(3, 'book3', 3 )

insert into @backupBook values(1, 'book1', 1 )
insert into @backupBook values(2, 'book2', 2 )

select * from @book
select * from @backupBook

delete a
from @book a 
INNER JOIN @backupBook b
  ON a.AuthorID = b.AuthorID
  and a.BookName = b.BookName
  and a.BookID = b.BookID

select * from @book
select * from @backupBook

从表中删除不匹配的数据

4 个答案: