select * from train_091203 A inner Join train_091203 b on A.trainNum=B.trainNum where A.station = '天津' and b.station='北京南'
select A.trainNum, A.type, A.startDriveTime, B.arriveTime, ABS(sum(B.km-A.km)) from train_091203 A Join (select * from train_091203 where station='北京南')B On A.trainNum=B.trainNum where A.station = '天津' Group by A.trainNum
from train_091203 A inner Join train_091203 b on A.trainNum=B.trainNum
where A.station = '天津' and b.station='北京南'
from train_091203 A Join (select * from train_091203 where station='北京南')B
On A.trainNum=B.trainNum where A.station = '天津' Group by A.trainNum