数据库中记录累加的问题

Question

select YMDHM,DTRN,D=(
select sum(DTRN) from a 
where YMDHM<=aa.YMDHM and datediff(day,YMDHM,a.YMDHM)=0)
from a aa

Answer 1

--改一下:select YMDHM,DTRN,D=(
select sum(DTRN) from a 
where YMDHM<=aa.YMDHM and datediff(day,YMDHM,aa.YMDHM)=0)
from a aa

Answer 2

--测试--测试数据
create table a(YMDHM Datetime,DTRN Numeric(5,1))
insert a  select '2004-4-8 23:00:00',  1
union all select '2004-4-9 00:00:00',  0
union all select '2004-4-9 01:00:00',0.5
union all select '2004-4-9 02:00:00',  1
union all select '2004-4-9 03:00:00',0.5
union all select '2004-4-9 04:00:00',1.5
go--查询
select YMDHM,DTRN,D=(
select sum(DTRN) from a 
where YMDHM<=aa.YMDHM and datediff(day,YMDHM,aa.YMDHM)=0)
from a aa
go--删除测试
drop table a/*--测试结果YMDHM                                                  DTRN    D       
------------------------------------------------------ ------- --------
2004-04-08 23:00:00.000                                1.0     1.0
2004-04-09 00:00:00.000                                .0      .0
2004-04-09 01:00:00.000                                .5      .5
2004-04-09 02:00:00.000                                1.0     1.5
2004-04-09 03:00:00.000                                .5      2.0
2004-04-09 04:00:00.000                                1.5     3.5（所影响的行数为 6 行）--*/

Answer 3

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