Question

我有一张列出合约日期的表格。合同可以有多个日期，所以我只想要最新的日期。

我尝试按合约排序日期排名，然后过滤以便我只获得第一排名，但我不断收到语法错误：

列名称'contractRank'无效。

SELECT MAX(contractEnded) AS contractEnded, contractID, contractStarted, contractEnded, userID, examID,
ROW_NUMBER() OVER (
                  partition by userID
                  ORDER BY MAX(contractEnded) desc)
                  AS contractRank
FROM examcontract es
WHERE examID = 92855231134
and es.contractRank = 1
GROUP BY  userID, examID, contractID, contractStarted, contractEnded

有没有办法在mssql 2012中执行此操作？

谢谢！

Answer 1

排名函数无法在查询中进行操作，您需要使用外部查询来操作任何排名函数。

此外，您不需要使用MAX（）函数来获取使用排名功能的最后日期，以下查询将返回表格中每个用户ID的最后合同结束日期。

SELECT contractEnded, contractID, contractStarted, contractEnded, userID, examID
FROM (
     SELECT contractEnded, contractID, contractStarted, contractEnded, userID, examID,
         ROW_NUMBER() OVER (partition by userID ORDER BY contractEnded desc)  AS contractRank
     FROM examcontract 
    WHERE examID = 92855231134
     )A
WHERE  A.contractRank = 1

正如Aaron在你的评论部分提到的那样，你也可以使用CTE（Common Table Expression）来达到相同的效果。

;WITH CTE AS 
 (
  SELECT contractEnded, contractID, contractStarted, contractEnded, userID, examID,
    ROW_NUMBER() OVER (partition by userID ORDER BY contractEnded desc)  AS contractRank
  FROM examcontract es
  WHERE examID = 92855231134
 )
SELECT contractEnded, contractID, contractStarted, contractEnded, userID, examID
FROM CTE 
WHERE contractRank = 1

列出具有最新日期的行

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