Question

我有两张桌子，车辆和阅读。

车辆表

VehicleId 名称 InitialReading

ABC 584
XYZ 900

阅读表

ReadingId 日期转移 VehicleId 阅读

2014-09-01 1 1 1234
2014-09-01 2 1 2230
2014-09-02 1 1 2500
2014-09-02 2 1 3004
2014-09-03 2 1 5000
2014-09-03 1 1 4000
2014-09-01 1 2 1000

现在我在结合阅读时遇到了问题。我在桌子上搜索VehicleId

例如VehicleId=1，则输出必须采用以下格式。

Date Shift OpeningReading ClosingReading

2014-09-01 1 584  1234 (if there are no opening for this date, I have to fetch the initial reading)   
2014-09-01 2 1234 2230    
2014-09-01 1 2230 2500
2014-09-01 2 2500 3004
2014-09-01 1 3004 4000
2014-09-01 2 4000 5000

我用CROSS APPLY

create table vehicle(vehicleId int identity(1,1),name varchar(25),initialReading int);
insert into vehicle values('ABC',584),('XYZ',900);


create table reading (readingId int identity(1,1),[date] date,vehicleId int,shiftId int,reading int);
insert into reading values ('2014-09-01',1,1,1234),('2014-09-01',1,2,2230), ('2014-09-02',1,1,2500),('2014-09-02',1,2,3004),('2014-09-03',1,2,5000),('2014-09-03',1,1,4000);

SQLFiddle of the said experiment

Answer 1

你已经有两张桌子..现在你想要两个表格，其中车辆id = 1

只使用子查询

select R.Date R.Shift,(select V.Initial Reading From Vehicle V where v.Vehicle id =R.Vehicle Id) as Initial Reading , R.Reading as Closing Reading from Reading Where Vehicle id=@Vehicle id

or 

set @Vehicle id=1

select R.Date R.Shift,(select V.Initial Reading From Vehicle V where v.Vehicle id =R.Vehicle Id) as Initial Reading , R.Reading as Closing Reading from Reading Where Vehicle id=1

sql server join只返回第二个表中的一行

1 个答案: