MySQL更新具有相同值的多行

Question

我有一个files表

(userID, fileID, fileName, folderID, folderName).

我想为发现重复的用户更新多行，例如

目前，我有userID=1 ，在'work' folderID of '1'的folderName下都有2 files ，

我想将folderName更新为'work1'但保持相同的folderID of '1' 。

这是我当前的sql语句，我无法使其正常工作：

UPDATE files SET fileFolder = '$folderName'  
WHERE folderID = '$folderID' AND userID = '$userID'

Answer 1

UPDATE files SET fileFolder = '$folderName'  
WHERE folderID = '$folderID' AND userID = '$userID'

您是否尝试使用folderName而不是设置fileFolder？ 如 ..

UPDATE files SET folderName= '$folderName'  
WHERE folderID = '$folderID' AND userID = '$userID'

Answer 2

如果工作文件夹多次，则需要将文件夹名称更新，例如将work更改为work1。 因此，您需要检查旧文件夹是否有多个。

尝试这样的事情（未经测试）：

  UPDATE files SET folderName= '$folderName'  
    WHERE folderID = '$folderID' AND userID = '$userID' AND ( 1 < (SELECT count(*) from files where folderID = $folderID and folderName='oldFolderName'))