How to update table when Email is on another table?

USE [ASPDryrun]
GO

  UPDATE [dbo].[Users]
    SET [ID] = [IU].[PersNo], 
        [C开发者_StackOverflowostCenter] = [CC].[CostCenterID], 
        [OrgUnit] = [OU].[OrgUnitID]
   FROM [dbo].[Users], 
        [dbo].[Import_UserData] AS [IU], 
        [dbo].[CostCenters] AS [CC], 
        [dbo].[OrgUnits] AS [OU]
  WHERE [CC].[ID] = [IU].[CostCtr]
    AND [OU].[ID] = [IU].[OrgUnit]
    AND [IU].[CorporateEmail] IN (SELECT [Email] 
                                    FROM [dbo].[Users])

GO

I want to update the info of some users when they have the email on the other table. But this query update all users and don't know what's wrong, can you help me? Thanks

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Would explicit joins work better? Just guessing, not sure what data is actually in these... Like

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]

---

Finally I could fix the problem with only another condition more. Here is the result:

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