NWPU SoftWareEngineering Database Designed ex1

select distinct city from location, (select toareacode,count(status) from call table1 where table1.callstarttime > '1989-10-17 18:00:00' and table1.callstarttime < '1989-10-17 19:00:00' and table1.status='f' group by toareacode) as res1, (select toareacode,count(status) from call table2 where tab