多表相乘的SQL，求大神帮助下。
------解决思路----------------------
DECLARE @SQL VARCHAR(MAX)
SET @SQL='SELECT F.C_NM'
SELECT @SQL=@SQL+',SUM(CASE G.A_NM WHEN '''+A_NM+''' THEN G.ZL END)*F.SL['+A_NM+']'
FROM(SELECT A_NM FROM(SELECT A_NM FROM D UNION ALL SELECT B_NM FROM E)T1 GROUP BY A_NM)T2
SET @SQL=@SQL+'FROM F LEFT JOIN(SELECT DM,A_NM,ZL FROM D UNION ALL SELECT DM,B_NM,ZL FROM E)G ON F.DM=G.DM '
SET @SQL=@SQL+'GROUP BY F.C_NM,F.SL'
PRINT @SQL
EXEC(@SQL)