thinkphp groupby demo

sql:

select cityid,cityname from tsh_city where cityid in(

select gs_cityid from tsh_greenschool group by gs_cityid 

);

 

 

thinkphp:      

 

$subquery=M('greenschool')->field('gs_cityid')->group('gs_cityid')->select(false);

     $citylist=M('city')->field('cityid,cityname')->where('cityid in '.$subquery)->select();

     $temp='';

     foreach ($citylist as $value) {

     $temp=$temp.$value['cityname'];

     }

     dump($temp);