Question

目前，我在sql server中有这个代码，它应该从数据库中获取值并将它们放到另一个数据库中。

Insert into AppleFinalX.[dbo].SalesFactTable(SalesType, TotalSales, SalesHDRDate, ProductSales, ProductID) 
SELECT AppleFinal.[dbo].SalesHDRTable.SalesType,
       AppleFinal.[dbo].SalesHDRTable.TotalSales,
       AppleFinal.[dbo].SalesHDRTable.SalesHDRDate,
       AppleFinal.[dbo].SalesDetailsTable.PurchaseAmount,
       AppleFinal.[dbo].ProductTable.ProductID
FROM AppleFinal.[dbo].SalesHDRTable, 
     AppleFinal.[dbo].SalesDetailsTable, 
     AppleFinal.[dbo].ProductTable

基本上，它从不同数据库（AppleFinal）的三个表中获取值，并将它们放在不同数据库（AppleFinalX）的表中。但不幸的是，它返回1000条记录而不是10条。任何人都知道为什么会这样？ :(所有表格各有10条记录，所以我很震惊地看到新表中的1000条记录......

Answer 1

正如其他人所评论的那样，您将每个表的每一行连接到每个其他表的每一行。那显然不是你想要的。使用JOIN命令是解决方案。像这样：

SELECT AppleFinal.[dbo].SalesHDRTable.SalesType,
   AppleFinal.[dbo].SalesHDRTable.TotalSales,
   AppleFinal.[dbo].SalesHDRTable.SalesHDRDate,
   AppleFinal.[dbo].SalesDetailsTable.PurchaseAmount,
   AppleFinal.[dbo].ProductTable.ProductID
FROM AppleFinal.[dbo].SalesHDRTable
    INNER JOIN AppleFinal.[dbo].SalesDetailsTable
        ON  AppleFinal.[dbo].SalesHDRTable.ID = AppleFinal.[dbo].SalesDetailsTable.SalesID
    INNER JOIN AppleFinal.[dbo].ProductTable
        ON AppleFinal.[dbo].SalesDetailsTable.ProductID = AppleFinal.[dbo].ProductTable.ID

Answer 2

明确说明你的连接要好得多：

INSERT INTO AppleFinalX.dbo.SalesFactTable
            (SalesType, TotalSales, SalesHDRDate, ProductSales, ProductID) 

SELECT sh.SalesType,
       sh.TotalSales,
       sh.SalesHDRDate,
       sd.PurchaseAmount,
       pt.ProductID

FROM AppleFinal.dbo.SalesHDRTable  sh
    LEFT JOIN   AppleFinal.dbo.SalesDetailsTable sd ON  sd.saleType = sh.saleType
    LEFT JOIN   AppleFinal.dbo.ProductTable pt      ON pt.ProductID = sh.ProductID

Answer 3

虽然我更愿意申请必要的加入，但也试试这个：

Insert into AppleFinalX.[dbo].SalesFactTable(SalesType, TotalSales, SalesHDRDate, ProductSales, ProductID) 
SELECT AppleFinal.[dbo].SalesHDRTable.SalesType,
       AppleFinal.[dbo].SalesHDRTable.TotalSales,
       AppleFinal.[dbo].SalesHDRTable.SalesHDRDate,
       AppleFinal.[dbo].SalesDetailsTable.PurchaseAmount,
       AppleFinal.[dbo].ProductTable.ProductID
FROM AppleFinal.[dbo].SalesHDRTable, 
     AppleFinal.[dbo].SalesDetailsTable, 
     AppleFinal.[dbo].ProductTable
group by AppleFinal.[dbo].SalesHDRTable.SalesType,
       AppleFinal.[dbo].SalesHDRTable.TotalSales,
       AppleFinal.[dbo].SalesHDRTable.SalesHDRDate,
       AppleFinal.[dbo].SalesDetailsTable.PurchaseAmount,
       AppleFinal.[dbo].ProductTable.ProductID

Select Insert Statement返回1000个字段而不是10个

3 个答案: