逐级汇总示例(用户定义函数法).sql

CREATE TABLE tb(ID int PRIMARY KEY,PID int,Num int)
INSERT tb SELECT 1,NULL,100
UNION ALL SELECT 2,1   ,200
UNION ALL SELECT 3,2   ,300
UNION ALL SELECT 4,3   ,400
UNION ALL SELECT 5,1   ,500
UNION ALL SELECT 6,NULL,600
UNION ALL SELECT 7,NULL,700
UNION ALL SELECT 8,7   ,800
UNION ALL SELECT 9,7   ,900
GO

--得到每个节点的编码累计
CREATE FUNCTION f_id()
RETURNS @t TABLE(ID int,Level int,SID varchar(8000))
AS
BEGIN
    DECLARE @Level int
    SET @Level=1
    INSERT @t SELECT ID,@Level,','+CAST(ID as varchar)+','
    FROM tb
    WHERE PID IS NULL
    WHILE @@ROWCOUNT>0
    BEGIN
        SET @Level=@Level+1
        INSERT @t SELECT a.ID,@Level,b.SID+CAST(a.ID as varchar)+','
        FROM tb a,@t b
        WHERE a.PID=b.ID
            AND b.Level=@Level-1
    END
    RETURN
END
GO

--调用函数实现实现累计
SELECT a.ID,a.PID,a.Num,SUM_Num=SUM(b.Num)
FROM tb a,f_id() a1,
    tb b,f_id() b1
WHERE a.ID=a1.ID
    AND b.ID=b1.ID
    AND b1.SID LIKE a1.SID+'%'
GROUP BY a.ID,a.PID,a.Num
/*--结果
ID          PID         Num         SUM_Num
---------------- ------------------ ------------------- --------------------
1           NULL       100         1500
2           1           200         900
3           2           300         700
4           3           400         400
5           1           500         500
6           NULL       600         600
7           NULL       700         2400
8           7           800         800
9           7           900         900
--*/