mssql group by求差值

1 -- 利用临时表求查值
2 CREATE TABLE #tab ([user_id] INT,[fengshu] INT)
3 INSERT INTO #tab([user_id],[fengshu]) SELECT [user_id],SUM(fengshu) FROM dbo.score WHERE kemu='yuwen' GROUP BY user_id ORDER BY user_id DESC 
4 INSERT INTO #tab([user_id],[fengshu]) SELECT [user_id],-(SUM(fengshu)) FROM dbo.score WHERE kemu='shuxue' GROUP BY user_id ORDER BY user_id DESC 
5 SELECT [user_id],SUM(fengshu) AS result FROM #tab GROUP BY user_id ORDER BY user_id DESC 
6 
7 --用完drop
8 DROP TABLE #tab

 

--利用case when求差值
SELECT [user_id],(SUM(CASE [kemu] WHEN 'yuwen' THEN fengshu ELSE 0 END )-SUM(CASE [kemu] WHEN 'shuxue' THEN fengshu ELSE 0 END )) AS result
    FROM dbo.score GROUP BY [user_id]