SQL Syntax -- Group By ... Custom Aggregate Functionality?

Answer 1

I don't know the answer off the top of my head, but my guess is that you mean need to use a sub-query, which could make it a very expensive query.

It may be easier to pull all the data in an use code to post-process it yourself.

Answer 2

select ft.ItemName,
       price
from   (select   ItemName,
                 Max(ItemPriceEffectiveDate) as MaxEff
        from     FunTable
        where    ItemPriceEffectiveDate <= GETDATE()
        group by ItemName) as d,
       FunTable as ft
where  d.MaxEff = ft.ItemPriceEffectiveDate;

Edit: Changed the query to actually work, assuming the price does not change more than once a day.

Answer 3

should work if you do

SELECT ItemName, MAX(ItemPriceEffectiveDate)
FROM FunTable
WHERE ItemPriceEffectiveDate < getDate()
GROUP BY ItemName

Answer 4

Something like this (don't have your names, but you get the idea) ...

WITH A (Row, Price) AS
(
  SELECT Row_Number() OVER (PARTITION BY Item ORDER BY Effective DESC) AS [RN],
         Price FROM Table2
  WHERE Effective <= GETDATE()
)
SELECT * FROM A WHERE A.Row = 1