SR004-没有索引用作IN谓词测试表达式的列可能会降低性能

Question

我对SQL还是很陌生，所以我收到了我的问题标题中所述的错误。

附件图像是我的sql命令。

如果我不使用IN， 我会收到另一个错误，那就是子查询返回的值超过1个...

我应该如何编写它，以免出现任何此类错误？

下面是SQLcode： 开始

   SELECT [c].[ChargeSubCategoryOID] ,[c].[Description], [c].[Qty], [c].[Uom], [c].[BeforeGovtSubsidy], [c].[AfterGovtSubsidy],

   [c].[ChargesIndicatorCode], [c].[ChargesIndicatorValue]

   FROM ChargeItems AS [c]

   WHERE

   [c].[ChargeSubCategoryOID] IN

   (

          SELECT [c].[OID]

          FROM ChargeSubCategories AS [c]

          WHERE

          [c].[ChargeCategoryOID] IN

          (

                 SELECT [cg].[OID]

                 FROM ChargeCategories AS [cg]

                 WHERE

                 [cg].[ChargeGroupOID] IN

                 (

                       SELECT [cg].[OID]

                       FROM ChargeGroups AS [cg]

                       WHERE

                       [cg].[InvoiceOID] IN

                       (

                              SELECT TOP(1)

                              [p].[OID]

                              FROM [Invoices] AS [p]

                              LEFT JOIN [Payors] AS [p.Payors] ON [p].[OID] = [p.Payors].[InvoiceOID]

                              LEFT JOIN [Details] AS [p.Details] ON [p].[OID] = [p.Details].[InvoiceOID]

                              WHERE ([p].[InvoiceReferenceNo] = @BillRefNo) AND ([p.Details].[IdentificationNoValue] = @Id)

                              ORDER BY [p].[CreationTime] DESC, [p].[OID], [p.Payors].[OID]       

                       )            

                 )     

   )

   )ORDER BY [c].[ChargeSubCategoryOID] ASC

END

感谢您的帮助！谢谢！

Answer 1

我已将您的IN替换为INNER JOIN。请注意，我已经更改了别名，因此它们都不同，以防止歧义。

唯一重要的一点是最后一个JOIN，因为我尚未对表Invoices进行内部联接，但三个左联接表为其赋予了别名，因此您可以将联接条件设置为SQL语句的其余部分。

SELECT it.ChargeSubCategoryOID ,it.Description, it.Qty, it.Uom, it.BeforeGovtSubsidy, 
       it.AfterGovtSubsidy, it.ChargesIndicatorCode, it.ChargesIndicatorValue
FROM ChargeItems AS it
     inner join ChargeSubcategories AS sc on sc.OID = it.ChargeSubCategoryOID
     inner join ChageCategories AS ct on ct.OID = sc.ChargeCategoryOID
     inner join ChargeGroups AS gr on gr.OID = ct.ChargeGroupOID
     inner join (select top 1 in.OID
                 from Invoices AS in
                      left join Payors AS py on py.InvoiceOID = in.OID
                      left join Details AS dt on dt.InvoiceOID = in.OID
                 where in.InvoiceReferenceNo = @BillRefNo AND dt.IdentificationNoValue = @Id
                 order by in.CreationTime desc, in.OID, py.OID
                ) AS in2 on in2.OID = gr.Invoice.OID