如航线表中:
字段:fromCityID,toCityID,LineNo
这里的出发城市和到达城市都是城市的ID城市表的字段:
CitName,CityEnName,CityID然后我想通过sql语句查义出航线的信息,以及城市的相关信息,如下LineNo, FromCityID, toCityID, fromCityName, fromCityEnName, toCityName, toCityEnName如何关连表?
字段:fromCityID,toCityID,LineNo
这里的出发城市和到达城市都是城市的ID城市表的字段:
CitName,CityEnName,CityID然后我想通过sql语句查义出航线的信息,以及城市的相关信息,如下LineNo, FromCityID, toCityID, fromCityName, fromCityEnName, toCityName, toCityEnName如何关连表?
from 航线表 a
left join 城市表 b on a.fromcityid = b.cityid
left join 城市表 c on a.tocityid = c.cityid
b.citname as fromcityname,b.cityenname as fromcityenname,
c.citname as tocityname,c.cityenname as tocityenname
from 航线表 a
left join 城市表 b on a.fromcityid=b.cityid
left join 城市表 c on a.tocityid=c.cityid
fromCityName = (select CitName from 城市表 n where CityID = m.fromCityID)
...
from 航线表 m