Question

我想用另一个表中的匹配条件更新一个表。另一个表具有多个记录，因此只需要匹配键的前1个。到目前为止，这是我尝试过的：

 UPDATE checkList 
 SET checkList.Answer = A.Answer,
    checkList.Response = A.Response,
    checkList.ANmbr = A.DisplayOrder
 FROM checkList  INNER JOIN  (SELECT TOP 1 QuestID, Answer, Response, DisplayOrder FROM TabAnswers WHERE QuestID = checkList.QID ORDER BY DisplayOrder) A
 ON A.QuestID = checkList.QID    
 WHERE checkList.auditid='158478' and checkList.Qtype = '0'

它没有从TabAnswers表中选择正确的数据。 TabAnswers对于给定的问题有多个答案，只需要在清单中填充第一个即可。我找到了这个答案，但它是从表中选择第一个，而不是匹配克里特里亚 How to update column coming from TOP 1 of another table

Answer 1

如果要从子查询的外部引用列，则需要使用CROSS APPLY代替INNER JOIN（或OUTER APPLY代替LEFT OUTER JOIN）。

始终在子查询中限定列也很重要。

UPDATE c 
 SET c.Answer = A.Answer,
     c.Response = A.Response,
     c.ANmbr = A.DisplayOrder
 FROM checkList  c
 CROSS APPLY (SELECT TOP 1 ta.QuestID, ta.Answer, ta.Response, ta.DisplayOrder FROM TabAnswers ta WHERE ta.QuestID = c.QID ORDER BY DisplayOrder) A
 WHERE c.auditid='158478' and c.Qtype = '0'

如何使用特定条件更新来自另一个表的TOP 1的列

1 个答案: