asked on

At a casual glance is there any way I can improve these SQL Joins?

Most notably the outer apply join that returns 1 row per call from a tabular function that crosses databases

SELECT a.Field1,
              b.Field2,
              c.Field3,
              d.Field4,
              e.Field5,
              f.Field6
		FROM
			[dbo].[vwVessel] a
			JOIN [dbo].[vwVesselOpenPosition] b ON b.VesselID = a.VesselID
			JOIN [dbo].[vwPort] c ON c.PortID=b.PortID
			JOIN [dbo].[tbl_Ref_Port] d on d.PortID = c.PortID
			LEFT JOIN [dbo].[vwUserDictionary] e ON e.UserDictionaryID = d.AreaUserDictionaryID
			OUTER APPLY [dbo].[udtfGetQ88VesselData](a.VesselName, a.IMO) f 
			LEFT JOIN [dbo].[udtfGetUserVesselList](@paramUserID) g on g.VesselID = a.VesselID
		WHERE
			ISNULL(b.IsHide,0)=0
			AND a.UserCompanyID = @paramUserCompanyID
			AND (@paramIsMyVessel = 0 OR g.VesselID IS NOT NULL)

Open in new window

Scott Pletcher

Make sure the udtfGetQ88VesselData function is an in-line tvf and not a multi-statement tvf.

Paul Mauriello

ASKER

Its a pretty sophisticated function, but ultimately returns 1 row can you elaborate?

Scott Pletcher

The function should be a single RETURN ( ...query... ) statement, with as complex a query as needed to produce the final result. Those types of functions are vastly more efficient than those that construct a table variable and return it to the caller.

Paul Mauriello

ASKER

It already does. Is the Outer Apply the best way to go? I tried switching it to a left join but then I got the "unique identifier could not be bound error" on the params I am passing into the function

ASKER CERTIFIED SOLUTION

Scott Pletcher

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

Vitor Montalvão

Are you having performance issues with this query?
If so, please post the query execution plan.

Paul Mauriello

ASKER

Here is the overall execution plan. Looks fine until it tries to reach over into the other database. Wasn't sure if Outer Apply was the best way to go. But if that's the best I can do given the fact its crossing databases, then that's the best I can do. I attached the file
PositionListExecutionPlan.sqlplan

SOLUTION

Vitor Montalvão

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

Paul Mauriello

ASKER

Thank you for all your help. The function is the one your both previously helped me optimize. So I think we have come full circle. Until we do a redesign of that database, I believe that is the best we can do for now.