Question

我正在尝试根据另一个表中的条目更新或插入一个表。但是当我尝试使用MERGE来实现这一目标时。我收到以下错误消息。

错误：MERGE语句尝试多次更新或删除同一行。当目标行与多个源行匹配时会发生这种情况。 MERGE语句不能多次更新/删除目标表的同一行。优化ON子句以确保目标行最多匹配一个源行，或使用GROUP BY子句对源行进行分组。

我是否必须在ON子句中包含更多条件？

代码：

 IF EXISTS (SELECT ShoppingCartNo FROM tbPOValidation WHERE ShoppingCartNo <> '')  
    BEGIN
    MERGE tbPOValidation AS t
    USING tbPOValidationTemp AS s 
    ON (CONVERT(VARCHAR(30),t.ShoppingCartNo)+CONVERT(VARCHAR(30),t.lineitemNo)+CONVERT(VARCHAR(30),t.PONo)) = 
    (CONVERT(VARCHAR(30),s.ShoppingCartNo)+CONVERT(VARCHAR(30),s.lineitemNo)+CONVERT(VARCHAR(30),s.PONo))
    --When records are matched, update 
    --the records if there is any change
    WHEN MATCHED AND (CONVERT(VARCHAR(30),t.ShoppingCartNo)+CONVERT(VARCHAR(30),t.lineitemNo)+CONVERT(VARCHAR(30),t.PONo)) = 
    (CONVERT(VARCHAR(30),s.ShoppingCartNo)+CONVERT(VARCHAR(30),s.lineitemNo)+CONVERT(VARCHAR(30),s.PONo)) 
    THEN 
    UPDATE SET t.SupplierName = s.SupplierName, t.DUNS = s.DUNS, t.PONo = s.PONo, t.LineItemNo = s.LineItemNo, t.PurchDocItemDesc = s.PurchDocItemDesc,
            t.POIssueDate = s.POIssueDate, t.DeliveryDate = s.DeliveryDate, t.PurchDocType = s.PurchDocType, t.MtrNo = s.MtrNo, t.Location = s.Location,
            t.PayTerms = s.PayTerms, t.BlanketNo = s.BlanketNo, t.BlanketLineItemNo = s.BlanketLineItemNo, t.ShoppingCartNo = s.ShoppingCartNo, 
            t.SHCItmNo = s.SHCItmNo, t.ItemPricing = s.ItemPricing, t.ItmPrcCurrency = s.ItmPrcCurrency, t.Per = s.Per, t.POValue = s.POValue, 
            t.POValueCurrency = s.POValueCurrency, t.Qty = s.Qty, t.UOM = s.UOM, t.MFGName = s.MFGName, t.MFGPartNO = s.MFGPartNO, t.Description = s.Description, 
            t.Remarks = s.Remarks, t.Accept = s.Accept, t.AcceptedBy = s.Duns, t.AcceptedOn = GETDATE(), t.RejectionReason = s.RejectionReason
    --When no records are matched, insert
    --the incoming records from s
    --table to t table
    WHEN NOT MATCHED BY TARGET THEN 
    INSERT (SupplierName, DUNS, PONo, LineItemNo, PurchDocItemDesc, POIssueDate, DeliveryDate, PurchDocType, MtrNo,
            Location, PayTerms, BlanketNo, BlanketLineItemNo, ShoppingCartNo, SHCItmNo, ItemPricing, ItmPrcCurrency, Per, POValue, POValueCurrency,
            Qty, UOM, MFGName, MFGPartNO, Description, Remarks, Accept, AcceptedBy, AcceptedOn, RejectionReason)
    VALUES (s.SupplierName, s.DUNS, s.PONo, s.LineItemNo, s.PurchDocItemDesc, s.POIssueDate, s.DeliveryDate, s.PurchDocType, s.MtrNo,
            s.Location, s.PayTerms, s.BlanketNo, s.BlanketLineItemNo, s.ShoppingCartNo, s.SHCItmNo, s.ItemPricing, s.ItmPrcCurrency, s.Per, s.POValue,
            s.POValueCurrency,s.Qty, s.UOM, s.MFGName, s.MFGPartNO, s.Description, s.Remarks, s.Accept, s.AcceptedBy, s.AcceptedOn, s.RejectionReason);
    END

Answer 1

字段的串联可能不是唯一的，即10 11 12将等于101 11 2.在字段之间放置特殊字符：

ON (CONVERT(VARCHAR(30),t.ShoppingCartNo)+'~' +CONVERT(VARCHAR(30),t.lineitemNo)+'~'+CONVERT(VARCHAR(30),t.PONo)) = 
    (CONVERT(VARCHAR(30),s.ShoppingCartNo)+'~' +CONVERT(VARCHAR(30),s.lineitemNo)+'~' +CONVERT(VARCHAR(30),s.PONo))

SQL：使用MERGE时出错

1 个答案: