Question

I have this query that returns the correct data, but I would like to filter it.

SELECT     TOP (100) PERCENT dbo.Reg_Master.id, dbo.Cart_Programs.cartid, dbo.Reg_Master.F_ID,   dbo.BlockPeriod.profileid, dbo.Reg_Master.FirstName, 
                      dbo.Reg_Master.LastName, dbo.BlockPeriod.startdate, dbo.Cart_Programs.blockid
FROM         dbo.Cart_Programs LEFT OUTER JOIN
                      dbo.Reg_Master ON dbo.Cart_Programs.cartid = dbo.Reg_Master.cartid LEFT OUTER JOIN
                      dbo.BlockPeriod ON dbo.Cart_Programs.blockid = dbo.BlockPeriod.id
WHERE     (dbo.BlockPeriod.profileid = xxx) AND (dbo.Reg_Master.F_ID = xxxx)
ORDER BY dbo.BlockPeriod.startdate

For each dbo.Reg_Master.id, I would like to return only the earliest dbo.BlockPeriod.startdate (that is today or later – in other words ignoring dates that have already passed) for each dbo.Reg_Master.id, I cannot seem to get it formatted correctly.

Answer 1

First of all, TOP 100 Percent does nothing, the optimizer will just ignore it.
Also, your left joins do not serve any purpose because your WHERE condition, so I have edited the SQL to use an inner join + cross apply vs an outer join + outer apply.

If I understand you correctly for each Reg_Master record, you want at most 1 record from BlockPeriod, where that 1 record is the closest date that is greater than today’s date.

If so, then what you are looking for is an APPLY table operator combined with TOP (1) as shown below:

UPDATED:

SELECT Reg_Master.id, 
       Cart_Programs.cartid, 
       Reg_Master.F_ID,   
       T.profileid, 
       Reg_Master.FirstName, 
       Reg_Master.LastName, 
       T.startdate, 
       Cart_Programs.blockid
FROM Cart_Programs 
JOIN Reg_Master  ON Cart_Programs.cartid  = Reg_Master.cartid
CROSS APPLY(
   SELECT TOP 1 * FROM BlockPeriod
    WHERE BlockPeriod.id = Cart_Programs.blockid
      AND BlockPeriod.profileid = xxx AND Reg_Master.F_ID = xxxx 
      AND BlockPeriod.startdate >= GETDATE()
 ORDER BY BlockPeriod.startdate ASC 
) AS T