Question

我遇到以下SQL查询的问题：

DELETE FROM table1 WHERE uid =
(SELECT table1.uid from table1 INNER JOIN table2 ON table2.user = table1.uid
INNER JOIN table3 ON table3.uid = table2.seminar WHERE table3.end_date < CURDATE()))

错误是：您不能在FROM子句

中为更新指定目标表'table1'

有人知道如何解决这个问题吗？

Answer 1

这可能不是最优雅的方式，但您可以在临时表中选择您的条件，然后在#MyTempTable中删除从哪里

SELECT table1.uid 
INTO #MyTemp
from table1 INNER JOIN table2 ON table2.user = table1.uid
INNER JOIN table3 ON table3.uid = table2.seminar WHERE table3.end_date < CURDATE())


DELETE FROM table1 
WHERE uid IN
(SELECT uid from #MyTemp)

DROP TABLE #MyTemp

Answer 2

您可以选择加入表格。

DELETE  table1
FROM    table1 
        INNER JOIN table2 
            ON table2.user = table1.uid
        INNER JOIN table3 
            ON table3.uid = table2.seminar
WHERE   table3.end_date < CURDATE()

Answer 3

试试这个： -

DELETE  table1 FROM    table1 INNER JOIN table2 ON table2.user = table1.uid
        INNER JOIN table3 ON table3.uid = table2.seminar
WHERE   table3.end_date < CURDATE()

Answer 4

我首选的语法是：

Delete deleteAlias
/* Select *         */
from table1 deleteAlias
where exists ( select null from table1 innerTable1 INNER JOIN table2 ON table2.user = innerTable1.uid
INNER JOIN table3 ON table3.uid = table2.seminar WHERE table3.end_date < CURDATE())   

AND deleteAlias.uid = innerTable1.uid

   )

如果采用这种方法，你可以用一个简单的“select *”来代替在运行删除之前删除的内容。

/* Delete deleteAlias */
Select *
from table1 deleteAlias
where exists ( select null from table1 innerTable1 INNER JOIN table2 ON table2.user = innerTable1.uid
INNER JOIN table3 ON table3.uid = table2.seminar WHERE table3.end_date < CURDATE())   

AND deleteAlias.uid = innerTable1.uid

   )

Answer 5

您无法在select子句中修改或删除临时模式下使用的表。你可以在这里看到解释和替代方案： MySQL Error 1093 - Can't specify target table for update in FROM clause

SQL错误：DELETE和SELECT FROM冲突

5 个答案: