UPDATE查询的WHERE子句中的SELECT查询

问题描述：

可能重复:
Mysql错误1093-无法指定FROM子句中用于更新的目标表

Possible Duplicate:
Mysql error 1093 - Can’t specify target table for update in FROM clause

将SELECT查询放在UPDATE查询的WHERE子句中时出现错误.

I am getting an error when putting SELECT query in WHERE clause of UPDATE query.

我的查询是这样的:

UPDATE `subschedulesseats` m
SET m.studentid='1'
WHERE m.`seatid`= (
    SELECT h.`seatid`
    FROM `subschedulesseats` h
    WHERE h.`sessiontime`='02:30~04:00'
    ORDER BY h.`seatid` ASC
    LIMIT 2,1
)

AND错误将显示如下:

AND Error will be shown is like this :

您不能在FROM子句中指定目标表'm'进行更新"

"You can't specify target table 'm' for update in FROM clause"

我已附上错误显示的快照.

I have attached a snap shot of the error display.

请问有人可以帮助我解决这个问题吗?

Please anyone can help me in this problem?

先谢谢您

答

实际上，您可以通过将其包装在子查询中来进行更新(因此为结果创建临时表)

Actually you can update it by wrapping it in a subquery (thus creating temporary table for the result)

UPDATE `subschedulesseats` m
SET m.studentid='1'
WHERE m.`seatid`= 
(
    SELECT seatID
    FROM
    (
        SELECT h.`seatid`
        FROM `subschedulesseats` h
        WHERE h.`sessiontime`='02:30~04:00'
        ORDER BY h.`seatid` ASC
        LIMIT 2,1
    ) s
)

或使用JOIN

UPDATE  `subschedulesseats` m
        INNER JOIN
        (
            SELECT seatID
            FROM
            (
                SELECT h.`seatid`
                FROM `subschedulesseats` h
                WHERE h.`sessiontime`='02:30~04:00'
                ORDER BY h.`seatid` ASC
                LIMIT 2,1
            ) s
        ) t ON m.seatID = t.seatID
SET     m.studentid = '1'

UPDATE查询的WHERE子句中的SELECT查询

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