Question

无法弄清楚我在这里做错了什么。它表示字段HasNoteDate无效。我只是希望它返回1，如果有一个日期，0如果没有，我希望它分组，所以我可以得到计数和贷款金额的总和。我已经查看了stackoverflow的答案，用于按案例分组，但没有人为我解决它。谢谢！

SELECT    dbo.BDONAMES.UserID, dbo.BRKRMAST.Tier, dbo.BDONAMES.REGION, COUNT(*) AS TierRegionCount, 
                      SUM(dbo.LOAN.LOAN_AMT) AS LoanAmtSum, dbo.LOAN.DEAL_STATUS, CASE WHEN dbo.WORKFLOW.NOTE_DATE IS NULL 
                      THEN 0 ELSE 1 END AS HasNoteDate
FROM         dbo.BRKRMAST INNER JOIN
                      dbo.BRKRREF ON dbo.BRKRMAST.BRKRMASTID = dbo.BRKRREF.BRKRMASTID INNER JOIN
                      dbo.LOAN ON dbo.BRKRREF.LoanId = dbo.LOAN.LoanId INNER JOIN
                      dbo.WORKFLOW ON dbo.LOAN.LoanId = dbo.WORKFLOW.LoanId LEFT OUTER JOIN
                      dbo.BDONAMES ON dbo.BRKRMAST.BDONAMESID = dbo.BDONAMES.BDONAMESID
WHERE     (LEN(dbo.BDONAMES.UserID) > 0) AND (dbo.BRKRMAST.Tier > 0) AND (LEN(dbo.BDONAMES.REGION) > 0)
GROUP BY dbo.BDONAMES.UserID, dbo.BRKRMAST.Tier, dbo.BDONAMES.REGION, dbo.LOAN.LOAN_AMT, dbo.LOAN.DEAL_STATUS, HasNoteDate
ORDER BY dbo.BDONAMES.UserID, dbo.BRKRMAST.Tier, dbo.BDONAMES.REGION

Answer 1

SQL查询执行的逻辑并不像通用编程语言那样简单

以下是查询的示例执行阶段：

在FROM CLAUSE
执行GROUP BY - 这会导致错误，因为此时未定义HasNoteDate
执行ORDER BY
执行SELECT - 仅在此阶段定义了列HasNoteDate

所以，您不能在GROUP BY中使用未定义的列HasNoteDate，您必须将其替换为您的语句(CASE WHEN dbo.WORKFLOW.NOTE_DATE IS NULL THEN 0 ELSE 1 END)，然后sql server将能够GROUP

Answer 2

SELECT    dbo.BDONAMES.UserID, dbo.BRKRMAST.Tier, dbo.BDONAMES.REGION, COUNT(*) AS TierRegionCount, 
                      SUM(dbo.LOAN.LOAN_AMT) AS LoanAmtSum, dbo.LOAN.DEAL_STATUS, CASE WHEN dbo.WORKFLOW.NOTE_DATE IS NULL 
                      THEN 0 ELSE 1 END AS HasNoteDate
FROM         dbo.BRKRMAST INNER JOIN
                      dbo.BRKRREF ON dbo.BRKRMAST.BRKRMASTID = dbo.BRKRREF.BRKRMASTID INNER JOIN
                      dbo.LOAN ON dbo.BRKRREF.LoanId = dbo.LOAN.LoanId INNER JOIN
                      dbo.WORKFLOW ON dbo.LOAN.LoanId = dbo.WORKFLOW.LoanId LEFT OUTER JOIN
                      dbo.BDONAMES ON dbo.BRKRMAST.BDONAMESID = dbo.BDONAMES.BDONAMESID
WHERE     (LEN(dbo.BDONAMES.UserID) > 0) AND (dbo.BRKRMAST.Tier > 0) AND (LEN(dbo.BDONAMES.REGION) > 0)
GROUP BY dbo.BDONAMES.UserID, dbo.BRKRMAST.Tier, dbo.BDONAMES.REGION, dbo.LOAN.DEAL_STATUS, CASE WHEN dbo.WORKFLOW.NOTE_DATE IS NULL 
                                                                                                        THEN 0 ELSE 1 END
ORDER BY dbo.BDONAMES.UserID, dbo.BRKRMAST.Tier, dbo.BDONAMES.REGION

按照您在select语句中定义的方式使用组中的列，否则SQL Server会尝试使用SELECT语句中找不到的字段对其进行GROUP，并抛出错误。

使用CASE和GROUP BY的SQL Server查询，字段无效？

2 个答案: