SELECT "непустые" FROM tbl UNION SELECT "пустые" FROM tbl UNION SELECT ctl2 FROM tbl WHERE not ctl2 is null GROUP BY ctl2
SELECT 1 as ks,"непустые" FROM tbl UNION SELECT 2,"пустые" FROM tbl UNION SELECT 3,ctl2 FROM tbl WHERE not ctl2 is null GROUP BY 3,ctl2
SELECT TOP 1 " непустые" FROM tbl UNION All SELECT TOP 1 " пустые" FROM tbl UNION All SELECT DISTINCT ctl2 FROM tbl WHERE not ctl2 is null