party songs

party_songs.sql

WITH Acc AS (
 SELECT s70.ord,
        song70Id = s70.songId,
        song80Id = s80.songId,
        song90Id = s90.songId,
        roundTime = s70.songTime + s80.songTime + s90.songTime
 FROM  (SELECT ord = Row_Number() OVER(ORDER BY songTime DESC),
               songId,
               songTime
        FROM   @songList
        WHERE  songDecade = 70) s70
 JOIN  (SELECT ord = Row_Number() OVER(ORDER BY songTime DESC),
               songId,
               songTime
        FROM   @songList
        WHERE  songDecade = 80) s80 ON s70.ord = s80.ord
 JOIN  (SELECT ord = Row_Number() OVER(ORDER BY songTime DESC),
               songId,
               songTime
        FROM   @songList
        WHERE  songDecade = 90) s90 ON s70.ord = s90.ord
)
SELECT  song70Id, song80Id, song90Id
FROM  Acc a
WHERE   (  SELECT  SUM(roundTime)
           FROM    Acc
           WHERE   ord >= a.ord) <= @partyTime + roundTime
ORDER   BY ord
-- SQL Server 2008