Re: Top 10 airports referenced from a table of flights

[Rick James]

Glad it helped.

This might fix my mistakes:

select x.apid, sum(x.ct) as ct
   from ( select src_apid as apid, count(*) as ct
             from flights
             GROUP BY src_apid
          UNION ALL
          select dst_apid as apid, count(*) as ct
             from flights
             GROUP BY dst_apid
        ) x
   group by apid
   order by ct desc
   limit 10;

Possible (if it works) it will run faster.