根据另一个表删除表中的所有行

Question

我似乎永远不记得这个查询!

我想删除table1中的所有行,其ID与Table2中的相同.

所以:

DELETE table1 t1
 WHERE t1.ID = t2.ID

我知道我可以做一个WHERE ID IN(SELECT ID FROM table2)但是如果可能的话我想用JOIN做这个查询.

Answer 1

DELETE t1 
FROM Table1 t1
JOIN Table2 t2 ON t1.ID = t2.ID;

我总是在delete语句中使用别名,因为它可以防止意外

DELETE Table1 

在运行之前未能突出显示整个查询时导致的.

Answer 2

DELETE Table1
FROM Table1
INNER JOIN Table2 ON Table1.ID = Table2.ID

Answer 3

ANSI SQL中没有解决方案在删除AFAIK中使用连接.

DELETE FROM Table1
WHERE Table1.id IN (SELECT Table2.id FROM Table2)

稍后编辑

其他解决方案(有时表现更快):

DELETE FROM Table1
WHERE EXISTS( SELECT 1 FROM Table2 Where Table1.id = Table2.id)

Answer 4

PostgreSQL的实现将是:

DELETE FROM t1
USING t2
WHERE t1.id = t2.id;

Answer 5

尝试这个：

DELETE Table1
FROM Table1 t1, Table2 t2
WHERE t1.ID = t2.ID;

或者

DELETE Table1
FROM Table1 t1 INNER JOIN Table2 t2 ON t1.ID = t2.ID;

Answer 6

我认为如果你尝试这样做，你可能会获得更多的性能

DELETE FROM Table1
WHERE EXISTS (
  SELECT 1
  FROM Table2
  WHERE Table1.ID = Table2.ID
)