== Quote from ros (ros060@gmail.com)'s article
> Hi,
> I need help in writing a query.
> The following query uses 2 tables and my try is pasted below; I don't
> understand how to use count, max functions here.
> "return the name of the airport with the most flights departing from
> it. Only return one row and one column of data."
> select a.name
> from flight_profiles f, airports a
> where f.flt_from = a.iata_code
> and f.flt_from
> order by f.flt_from DESC
> LIMIT 1;
> CREATE TABLE `my-database`.`airports` (
> `IATA_CODE` varchar(3) default NULL,
> `NAME` varchar(30) default NULL,
> `CTY_IATA_CODE` varchar(3) default NULL,
> ) ENGINE=InnoDB DEFAULT CHARSET=latin1;
> CREATE TABLE `my-database`.`flight_profiles` (
> `FLP_ID` decimal(8,0) default NULL,
> `FLT_NUMB` decimal(4,0) default NULL,
> `SEATS` int(11) default NULL,
> `PRICE_CODE` varchar(3) default NULL,
> `FLT_FROM` varchar(3) default NULL,
> `FLT_TO` varchar(3) default NULL,
> `depart` datetime default NULL,
> `arrive` datetime default NULL
> ) ENGINE=InnoDB DEFAULT CHARSET=latin1;
> Thanks in advance.
> ros

this is relatively simple:
select name from airports join flight_profiles on flt_from = iata_code group by
iata_code order by count(iata_code) desc limit 1;

hope this helps