BOM数据排序及分级显示

--查询处理的存储过程
CREATE PROC P_QRY
AS
DECLARE @t TABLE(Parent_item varchar(10),Level int,Path varchar(8000))
DECLARE @l int
SET @l=0
INSERT @t SELECT DISTINCT Parent_item,@l,RIGHT(SPACE(20)+Parent_item,20)
FROM BomSub a
WHERE NOT EXISTS(
    SELECT * FROM BomSub WHERE Sub_item=a.Parent_item)
WHILE @@ROWCOUNT>0
BEGIN
    SET @l=@l+1
    INSERT @t SELECT a.Sub_item,@l,+RIGHT(SPACE(20)+a.Sub_item,20)
    FROM BomSub a,@t b
    WHERE a.Parent_item=b.Parent_item AND =@l-1
END
SELECT Parent_item=CASE Level WHEN 0 THEN '' ELSE '|'+REPLICATE('-',Level) END+Parent_item,
    Level
FROM @t
ORDER BY Path
GO

--调用
EXEC P_QRY