Btw, you might want to seriously consider using "UNION ALL" there rather than UNION. I think you are going to force a massive sort of all the rows by using "UNION".
SQL DBA,SQL Server MVP(07, 08, 09) Prosecutor James Blackburn, in closing argument in the Fatal Vision murders trial:
If in the future, you should cry a tear, cry one for them [the murder victims]. If in the future, you should say a prayer, say one for them. And if in the future, you should light a candle, light one for them.