加入这些表时为什么会出现错误？

Question

我正在尝试加入这两个表，但我收到错误代码？

SELECT LoanNumber, LetterDescription, LetterID, LetterDate, LetterProcessingDate
FROM PortfolioData.dbo.LetterData L
WHERE LetterID IN ('DF013', 'LM002')
LEFT JOIN MainServicing
ON Letterdata.LoanNumber = MainServicing.Loannumber

SELECT Loannumber,Lo_TypeDesc,Inv_ID,Investor_Desc,NPDD,UPB,cast(Date_Archived as date) as Date_Archived
FROM PortfolioData.dbo.MainServicing
WHERE Lo_TypeDesc IN ('USDA RHS') OR Investor_Desc IN ('FNMA','FHLMC')
AND (DATEDIFF(day,LetterDate,Date_Archived)<30)
 

Answer 1

SELECT L.LoanNumber, L.LetterDescription, L.LetterID, L.LetterDate, LetterProcessingDate
FROM PortfolioData.dbo.LetterData L  <---- Alias Here
WHERE LetterID IN ('DF013', 'LM002')
LEFT JOIN MainServicing M <---- Alias Here (Add it)
ON L.LoanNumber = M.Loannumber

您在 from 语句中有别名，请尝试在 LoanNumber 上使用别名 L 以及特定于 select 语句的其他字段。 我也会考虑添加 M 或一些别名。 请注意，您有 LoanNumber 看起来它位于两个表中，因此您需要对其进行限定，以便 select 知道 go 到哪个表。