Question

I know I have duplicate results from this query because the tables ReleaseHistory and IterationHistory have multiple records per ReleaseID and IterationID. I would like to only select the records with max date from dbo.ReleaseHistory and dbo.IterationHistory. How would I do that in this query? SQL SERVER 2008

SELECT     dbo.Assignable.AssignableID AS ID,
           dbo.EntityType.Abbreviation AS Entity, 
           dbo.General.Name, dbo.Assignable.Effort, 
           dbo.Assignable.EffortCompleted, 
           dbo.Assignable.EffortToDo, 
           dbo.EntityState.Name AS State, 
           dbo.ReleaseHistory.Name AS Release,   
           dbo.IterationHistory.Name AS Iteration, 
           dbo.General.CustomField3 AS [Scrum Team]
FROM       dbo.Assignable INNER JOIN
           dbo.General ON dbo.Assignable.AssignableID = 
             dbo.General.GeneralID INNER JOIN
           dbo.EntityType ON dbo.General.EntityTypeID = 
             dbo.EntityType.EntityTypeID INNER JOIN
           dbo.EntityState ON dbo.Assignable.EntityStateID = 
             dbo.EntityState.EntityStateID AND 
           dbo.EntityType.EntityTypeID = 
             dbo.EntityState.EntityTypeID INNER JOIN
           dbo.ReleaseHistory ON dbo.Assignable.ReleaseID = 
             dbo.ReleaseHistory.ReleaseID INNER JOIN
           dbo.IterationHistory ON 
             dbo.Assignable.IterationID = 
             dbo.IterationHistory.IterationID LEFT OUTER JOIN
           dbo.CustomField ON dbo.General.CustomField3 = 
             dbo.CustomField.CustomFieldID
WHERE     (dbo.Assignable.ProjectID = 4054)
GROUP BY dbo.Assignable.AssignableID, 
           dbo.EntityType.Abbreviation, 
           dbo.General.Name, 
           dbo.Assignable.Effort, 
           dbo.Assignable.EffortCompleted, 
           dbo.Assignable.EffortToDo, 
           dbo.EntityState.Name, 
           dbo.ReleaseHistory.Name, 
           dbo.IterationHistory.Name, 
           dbo.General.CustomField3

Answer 1

Brian,

I am amusing you are doing this in MS SQL and there will always be at least one record in ReleaseHistory and IterationHistory tables. If assumptions are correct then you can simply use CROSS APPLY to get top 1 record from both tables.

SELECT
    dbo.Assignable.AssignableID AS ID ,
    dbo.EntityType.Abbreviation AS Entity ,
    dbo.General.Name ,
    dbo.Assignable.Effort ,
    dbo.Assignable.EffortCompleted ,
    dbo.Assignable.EffortToDo ,
    dbo.EntityState.Name AS State ,
    Release ,
    Iteration ,
    dbo.General.CustomField3 AS [Scrum Team]
FROM
    dbo.Assignable 

    INNER JOIN dbo.General ON  dbo.Assignable.AssignableID = dbo.General.GeneralID 
    INNER JOIN dbo.EntityType ON  dbo.General.EntityTypeID = dbo.EntityType.EntityTypeID 
    INNER JOIN dbo.EntityState ON  dbo.Assignable.EntityStateID = dbo.EntityState.EntityStateID 
        AND dbo.EntityType.EntityTypeID = dbo.EntityState.EntityTypeID 
    CROSS APPLY( SELECT TOP 1 name Release FROM ReleaseHistory WHERE ReleaseID = Assignable.ReleaseID ORDER BY MaxDateColumn) a
    CROSS APPLY( SELECT TOP 1 name Iteration FROM IterationHistory WHERE IterationID = Assignable.IterationID ORDER BY MaxDateColumn) b
    LEFT OUTER JOIN dbo.CustomField ON  dbo.General.CustomField3 = dbo.CustomField.CustomFieldID
WHERE
    ( dbo.Assignable.ProjectID = 4054 )
GROUP BY
    dbo.Assignable.AssignableID ,
    dbo.EntityType.Abbreviation ,
    dbo.General.Name ,
    dbo.Assignable.Effort ,
    dbo.Assignable.EffortCompleted ,
    dbo.Assignable.EffortToDo ,
    dbo.EntityState.Name ,
    dbo.ReleaseHistory.Name ,
    dbo.IterationHistory.Name ,
    dbo.General.CustomField3