如果左外部连接为true，如何交叉应用

Question

I have a table called serviceEntry and table Called ServiceEntryPart which has a one to many relationship with the later. The problem is I want to cross apply only if the left outer statement is true.

So if I pass a part id and a service type id, it should only retun records where there is a true match, whats happeneing is if pass a partid and a service type id which did not exist for the specific record which has the part, I am getting results which did not have the part id passes but the records which contained the service type. If I pass the correct service type for the part then I get correct results.

ServiceEntry
ID
XYZ
XYZ

ServiceEntrPart    Sample Data
ID                 1
ServiceEntrID      10
ServiceEntryPart   1,2,3

   IF (@SelectedSystemIDs = '')                        
      begin        
          SET @SelectedSystemIDs = NULL         
      END         

IF (@SelectedPartsIDs = '')                        
  begin        
      SET @SelectedPartsIDs = NULL         
  END         

IF(@UserRoleID = 1)    
 BEGIN     
  SET @PlatformID = 1     
  END  

IF(@UserRoleID = 2)  
BEGIN  
SET @PlatformID = 2  
END  

IF (@UserRoleID = 3)    
BEGIN    
SET @PlatformID = 12    
END   

IF(@UserRoleID = 4)
BEGIN 
SET @PlatformID = 3
END

IF(@UserRoleID = 5)
BEGIN 
SET @PlatformID = 4
END

IF(@UserRoleID = 6)
BEGIN 
SET @PlatformID = NULL
END
--SET @Reconciled = 'R'

IF(@Reconciled='R')                            
 set @ReconciledValue=1                            
ELSE IF(@Reconciled='N')                            
 set @ReconciledValue=0   
ELSE IF(@Reconciled = 'A')
 set @ReconciledValue = null                         

--SET @ServiceTypes = '9'

IF @ServiceTypes = ''                        
  SET @ServiceTypes = NULL                          

IF @ServiceTypes IS NULL                   
  SET @flag = 2                  
 ELSE                    
 set @flag = 100                  

 IF (@SelectedSystemIDs = '')                    
    begin    
      SET @SelectedSystemIDs = NULL     
    END  

  Select     
   se.ID as ServiceEntryID,    
   se.ServiceDateTime,
   se.ReasonForFailure,
   se.ActionTaken,
   se.VerificationPerformed,
   se.TSBNumber,
   se.ISANumber,
   (SELECT     
  CAST(ID AS varchar(6)) + ' ~ ' + PartDescriptionWithParent FROM [RunLogTest].[dbo].[Part]       
    where id= sep.PartID) as PartDescriptionWithParent ,       
   (SELECT SystemFullName from System WHERE ID=se.SystemID
   )as SystemName,    
   se.Reconciled,
   se.CreatedDate,
   se.ClosedDate,
   se.UpdatedDate,
   se.ServiceHours,
   se.ServiceMinutes     
   FROM     
   [ServiceEntry] se left outer JOIN  
   ServiceEntryPart sep  ON se.ID = sep.ServiceEntryID   
   INNER JOIN SystemModule ON sep.SystemModuleID = SystemModule.ID  
   INNER JOIN System ON SystemModule.SystemID = System.ID 
   CROSS apply
   dbo.SplitStrings_Moden(sep.ServiceTypeIDs, N',') M2
   JOIN  dbo.SplitStrings_Moden(@ServiceTypes, N',') P ON (M2.Item = P.Item   or @ServiceTypes IS NULL)
   where se.ID=ServiceEntryID AND (se.Active = 1)
   AND (@ReconciledValue IS NULL OR se.Reconciled = @ReconciledValue)
   AND (@SelectedSystemIDs IS NULL OR  se.SystemID IN(select  * from dbo.SplitInts_RBAR_1(@SelectedSystemIDs, ',')))
   AND (@SelectedPartsIDs IS NULL or sep.PartID IN(select * from dbo.SplitInts_RBAR_1(@SelectedPartsIDs, ',')))
   AND (se.ServiceDateTime between @StartDate and @EndDate)
   AND ((@PlatformID IS NULL) OR  (System.PlatformID = @PlatformID) OR (@PlatformID = 12 AND System.PlatformID <= 2))  
   order by se.CreatedDate desc

Answer 1

Without any ability to test this I would propose 2 methods, one is rarely used so you might want to ignore it.

You form an outer join between se and sep , so to retain that outer join relationship you need to ensure anything joining to sep also permits the outer join. That would require more left joins, and an outer apply, like this:

-- common approach
FROM [ServiceEntry] se
      LEFT OUTER JOIN ServiceEntryPart sep
                  ON se.ID = sep.ServiceEntryID
      LEFT OUTER JOIN JOIN SystemModule
                  ON sep.SystemModuleID = SystemModule.ID
      LEFT OUTER JOIN JOIN System
                  ON SystemModule.SystemID = System.ID
      OUTER APPLY dbo.SplitStrings_Moden(sep.ServiceTypeIDs, N',') M2
      LEFT OUTER JOIN dbo.SplitStrings_Moden(@ServiceTypes, N',') P
                  ON (M2.Item = P.Item OR @ServiceTypes IS NULL)

OR (untested!) you can use a less used approach which involves moving the sequence of ON statements. What this does is changes the precedence of operation, and here I have shown brackets to highlight this. In effect the joins inside the brackets are performed to construct a derived table THEN that is outer joined to se

-- much less common           
FROM [ServiceEntry] se
      LEFT OUTER JOIN ServiceEntryPart sep
              (
                  INNER JOIN SystemModule
                              ON sep.SystemModuleID = SystemModule.ID
                  INNER JOIN System
                              ON SystemModule.SystemID = System.ID
                  CROSS APPLY dbo.SplitStrings_Moden(sep.ServiceTypeIDs, N',') M2
                  JOIN dbo.SplitStrings_Moden(@ServiceTypes, N',') P
                              ON (M2.Item = P.Item OR @ServiceTypes IS NULL)
              )
              ON se.ID = sep.ServiceEntryID

Whilst I believe either will work the first option is probably the most maintainable as it is easier for most folks to grasp.

However, do note that there is a condition in your where clause that would invalidate all outer joins IF @SelectedPartsIDs is not null:

  AND (@SelectedPartsIDs IS NULL
        OR sep.PartID IN (
              SELECT * FROM dbo.SplitInts_RBAR_1(@SelectedPartsIDs, ',')
                         )
      )

Answer 2

...
FROM dbo.[ServiceEntry] se
    left outer JOIN (
        dbo.ServiceEntryPart sep
        CROSS apply dbo.SplitStrings_Moden(sep.ServiceTypeIDs, N',') M2
    ) ON se.ID = sep.ServiceEntryID
...