IF EXISTS (SELECT 1 FROM SYSOBJECTS WHERE name = 'tba')
BEGIN
    DROP TABLE tba
END
GO
CREATE TABLE tba
(
    OperationAreaName VARCHAR(100),
    StationName VARCHAR(100),
    ReceiveTime VARCHAR(100),
    InPipePressure FLOAT,
    AccumulateWater INT
)
GO
INSERT INTO tba
SELECT '第二采油作业区',    '枣三注水站',    '2012-07-03 09:00:00.000',    0.4,    67 UNION
SELECT '第二采油作业区',    '枣三注水站',    '2012-07-03 10:00:00.000',    0.4,    58 UNION
SELECT '第二采油作业区',    '枣四注水站',    '2012-07-03 09:00:00.000',    0.4,    45 UNION
SELECT '第二采油作业区',    '枣四注水站',    '2012-07-03 10:00:00.000',    0.4,    45 UNION
SELECT '第二采油作业区',    '枣五注水站',    '2012-07-03 09:00:00.000',    0.4,    80 UNION
SELECT '第二采油作业区',    '枣五注水站',    '2012-07-03 10:00:00.000',    0.4,    79 UNION
SELECT '第二采油作业区',    '家五接转站',    '2012-07-03 09:00:00.000',    0.4,    57 UNION
SELECT '第二采油作业区',    '家五接转站',    '2012-07-03 10:00:00.000',    0.4,    56

GO

SELECT OperationAreaName,ReceiveTime,SUM(InPipePressure * AccumulateWater) / SUM(AccumulateWater * 1.0) AS value
FROM tba
GROUP BY OperationAreaName,ReceiveTime

------解决方案--------------------
表示看不太懂你的逻辑
9:00 
(((67*0.4)+(45*0.4)+(80*0.4)+(57*0.4))/(67+45+57))
10:00为什么不是：
(((58*0.4)+(45*0.4)+(79*0.4)+(56*0.4))/(58+45+56))

------解决方案--------------------

SQL code

--> 测试数据：[test]
if object_id('[test]') is not null 
drop table [test]
create table [test](
[OperationAreaName] varchar(14),
[StationName] varchar(10),
[ReceiveTime] datetime,
[InPipePressure] numeric(2,1),
[AccumulateWater] int
)
go
insert [test]
select '第二采油作业区','枣三注水站','2012-07-03 09:00:00.000',0.4,67 union all
select '第二采油作业区','枣三注水站','2012-07-03 10:00:00.000',0.4,58 union all
select '第二采油作业区','枣四注水站','2012-07-03 09:00:00.000',0.4,45 union all
select '第二采油作业区','枣四注水站','2012-07-03 10:00:00.000',0.4,45 union all
select '第二采油作业区','枣五注水站','2012-07-03 09:00:00.000',0.4,80 union all
select '第二采油作业区','枣五注水站','2012-07-03 10:00:00.000',0.4,79 union all
select '第二采油作业区','家五接转站','2012-07-03 09:00:00.000',0.4,57 union all
select '第二采油作业区','家五接转站','2012-07-03 10:00:00.000',0.4,56
go


select 
    OperationAreaName,
    ReceiveTime,
    sum(InPipePressure*AccumulateWater)/SUM([AccumulateWater]) as Total
from 
    test
group by
    OperationAreaName,
    ReceiveTime
/*
OperationAreaName    ReceiveTime    Total
-----------------------------
第二采油作业区    2012-07-03 09:00:00.000    0.400000
第二采油作业区    2012-07-03 10:00:00.000    0.400000
*/