Mysql 使用联接更新SQL查询

下面是我的SELECT语句，它列出了我试图更改的内容

SELECT

t1.`qid`,
t1.`gid` as 'incorrect gid',
t1.`question` as 'subquestion',
t1.`parent_qid`,

t2.`qid`,
t2.`gid` as 'correct gid',
t2.`question`

FROM `questions` as t1

LEFT JOIN `questions` as t2 ON t1.`parent_qid` = t2.`qid`

WHERE t1.`sid` = '33844' AND t1.`gid` NOT IN ('1306','1317','1319','1320','1321','1322','1323','1324','1325','1326','1327','1328','1329','1330','1331','1332','1333','1334','1335''1334','1335','1336', '1337','1338','1339','1340')

我想使用UPDATE语句将所有“不正确的gid”替换为“正确的gid”

这是我尝试过的更新语句，但无法开始工作

UPDATE `questions` as t1 

SET `gid` = t2.`gid`

FROM

`questions` as t1
LEFT JOIN
`questions` as t2 ON t1.`parent_qid` = t2.`qid`

WHERE t1.`sid` = '33844' AND t1.`gid` NOT IN ('1306','1317','1319','1320','1321','1322','1323','1324','1325','1326','1327','1328','1329','1330','1331','1332','1333','1334','1335''1334','1335','1336', '1337','1338','1339','1340')

基本上，所有子行的gid（组id）都不正确，需要修复。但是引用父级的所有行（因为父级和子级在同一个表中）都将具有正确的组id

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因此，我必须将父groupid连接到每个子行。

MySQL中的正确语法：

UPDATE `questions` as t1 LEFT JOIN
       `questions` as t2 ON t1.`parent_qid` = t2.`qid`
    SET t1.`gid` = t2.`gid`
WHERE t1.`sid` = '33844' AND
      t1.`gid` NOT IN ('1306','1317','1319','1320','1321','1322','1323','1324','1325','1326','1327','1328','1329','1330','1331','1332','1333','1334','1335''1334','1335','1336', '1337','1338','1339','1340')

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显然你不应该用这个盒子说“谢谢”，但我还是要用它！谢谢成功了。