Multiple documents, each document a number of details, cycle, to determine the beginning of each document

Apply multiple documents, each document multiple details, to the details of each document, business processing. Circular data, identifying the first detail of each document.

--CREATE TABLE ABC--(--A int,--B int,--C int--)--Insert ABC Select ' 1 ', ' a ', null--Insert ABC Select ' 1 ', ' ten ', null--Insert ABC Select ' 2 ', ' + ', null--Insert ABC Select ' 2 ', ' 5 ', nullif exists(Select *  fromsysobjectswhereId=object_id(N'tempdb: #ttt') ) Drop Table#tttDECLARE @sid INT,@sno INT,@preid int,@curid int,@ccid int,@ctotal intSelect IDENTITY(int,1,1) asFid*  into#ttt fromAbcOrder  byAASCBdescSET @sno=@ @rowcountSET @sid=1Set @preid=0Set @ctotal=0 while @sid<=@snoBEGINSelect @curid=A from#tttwhereFid=@sidSelect @ccid=B from#tttwhereFid=@sidif @preid<>@curidbeginSet @ctotal=@ccidSet @preid=@curidEndElsebeginSet @ctotal=@ctotal-@ccidEndUpdate#tttSetC=@ctotal whereFid=@sidSET @sid=@sid+1ENDSelect *  from#tttDrop Table#ttt

Fid	A	B	C
1	1	20	20
2	1	10	10
3	2	15	15
4	2	5	10

Multiple documents, each document a number of details, cycle, to determine the beginning of each document