sql nested select or join

Hi
I have the following code which runs and I see the results for a second,and then it errors with
Msg 512, Level 16, State 1, Line 82
Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.


 select dStartTime,dEndTime,iMaxSpeed,iDistance,iAverageSpeed,nStartEventInst,nEndEventInst,vpkDeviceID,
 (	
	Select vehiclePosition
	from tblTrackingData 
	where nEventInst = tm.nStartEventInst
) as startPos

 FROM tblTrip_Master tm where vpkDeviceID = '862170018835676'

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The above Nested select gets the StartPosition, i also need to another nested select or join to get the End Position

Any help appreciated
websssAsked:
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Aneesh RetnakaranDatabase AdministratorCommented:
select dStartTime,dEndTime,iMaxSpeed,iDistance,iAverageSpeed,nStartEventInst,nEndEventInst,vpkDeviceID,
FROM tblTrip_Master tm
INNER JOIN  (      
      SELECT nEventInst, MIN(vehiclePosition) AS StartPos ,MAX(vehiclePosition) AS LastPos
      from tblTrackingData
      
) as n
ON n.nEventInst = tm.nStartEventInst
WHERE  vpkDeviceID = '862170018835676'
0
Ivo StoykovCommented:
Hi,

The error is obvious -
Subquery returned more than 1 value.
you have to add some where clause that limit it to one row or add to it SELECT TOP 1 * FROM [table]

select dStartTime,dEndTime,iMaxSpeed,iDistance,iAverageSpeed,nStartEventInst,nEndEventInst,vpkDeviceID,
 (	
	Select Top(1) vehiclePosition
	from tblTrackingData 
	where nEventInst = tm.nStartEventInst
) as startPos

 FROM tblTrip_Master tm where vpkDeviceID = '862170018835676'

Open in new window

HTH

Ivo Stoykov
0

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ste5anSenior DeveloperCommented:
Start with a normal JOIN to get an idea of the data:

SELECT  TM.dStartTime ,
        TM.dEndTime ,
        TM.iMaxSpeed ,
        TM.iDistance ,
        TM.iAverageSpeed ,
        TM.nStartEventInst ,
        TM.nEndEventInst ,
        TM.vpkDeviceID ,
        TD.vehiclePosition
FROM    tblTrip_Master TM
        LEFT JOIN tblTrackingData TD ON TD.nEventInst = TM.nStartEventInst
WHERE   TM.vpkDeviceID = '862170018835676';

Open in new window


Your first query returned more than 1 row, thus your definition of "Start" seems to be unprecise or wrong. Maybe you need a further predicate in the JOIN condition รก la TD.vpkDeviceID = TM.vpkDeviceID.
0
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Microsoft SQL Server

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