Question

I need a way to take a resultset of KeyIDs and divide it up as equally as possible and update records differently for each division based on the KeyIDs. In other words, there is

SELECT KeyID
FROM   TableA
WHERE (some criteria exists)

I want to update TableA 3 different ways by 3 equal portions of KeyIDs.

UPDATE TableA
SET    FieldA = Value1
WHERE  KeyID IN (the first 1/3 of the SELECT resultset above)

UPDATE TableA
SET    FieldA = Value2
WHERE  KeyID IN (the second 1/3 of the SELECT resultset above)

UPDATE TableA
SET    FieldA = Value3
WHERE  KeyID IN (the third 1/3 of the SELECT resultset above)

or something to that effect. Thanks for any and all of your responses.

Answer 1

With TiledItems As
    (
        Select KeyId
            , NTILE(3) OVER( ORDER BY ... ) As NTileNum
        From TableA
        Where ...
    )
Update TableA
Set FieldA = Case TI.NTileNum
                    When 1 Then Value1
                    When 2 Then Value2
                    When 3 Then Value3
                    End
From TableA As A
    Join TiledItems As TI
        On TI.KeyId = A.KeyId