Sql 当电子邮件位于另一个表上时，如何更新表？

我想更新一些用户的信息，当他们在另一个表上有电子邮件时。但是这个查询更新了所有用户，不知道出了什么问题，你能帮我吗？谢谢，显式连接会更好吗？只是猜测，不确定这些数据中到底有什么。。。 像

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最后，我可以用另外一个条件来解决这个问题。结果如下：

USE [ASPDryrun]
GO

  UPDATE [dbo].[Users]
    SET [ID] = [IU].[PersNo], 
        [CostCenter] = [CC].[CostCenterID], 
        [OrgUnit] = [OU].[OrgUnitID]
   FROM [dbo].[Users], 
        join [dbo].[Import_UserData] AS [IU] on [IU].[CorporateEmail]=users.[email]
        join [dbo].[CostCenters] AS [CC] on [CC].[ID] = [IU].[CostCtr]
        join [dbo].[OrgUnits] AS [OU] on [OU].[ID] = [IU].[OrgUnit]

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您没有任何将

dbo.Users

表与查询中的其他表关联的联接条件。也许我应该添加此条件：

和[IU].[CorporateEmail]=[dbo].[Users].[Email]

Email是唯一的比较字段

USE [ASPDryrun]
GO

  UPDATE [dbo].[Users]
    SET [ID] = [IU].[PersNo], 
        [CostCenter] = [CC].[CostCenterID], 
        [OrgUnit] = [OU].[OrgUnitID]
   FROM [dbo].[Users], 
        join [dbo].[Import_UserData] AS [IU] on [IU].[CorporateEmail]=users.[email]
        join [dbo].[CostCenters] AS [CC] on [CC].[ID] = [IU].[CostCtr]
        join [dbo].[OrgUnits] AS [OU] on [OU].[ID] = [IU].[OrgUnit]

USE [ASPDryrun]
GO
        UPDATE [dbo].[Users]
        SET [ID] = [IU].[PersNo],
            [CostCenter] = [CC].[CostCenterID],
            [OrgUnit] = [OU].[OrgUnitID]
        FROM [dbo].[Import_UserData] AS [IU],
             [dbo].[CostCenters] AS [CC],
             [dbo].[OrgUnits] AS [OU],
             [dbo].[Users] AS [U]
        WHERE [CC].[EricssonID] = [IU].[CostCtr]
          AND [OU].[EricssonID] = [IU].[OrgUnit]
          AND [IU].[CorporateEmail] = [U].[Email]
        GO