CREATE TABLE airports (name VARCHAR, city VARCHAR, apid VARCHAR)
CREATE TABLE routes (src_apid VARCHAR)

Find the name and city of the airport which is the source for the most number of flight routes.
SELECT T1.name, T1.city, T2.src_apid FROM airports AS T1 JOIN routes AS T2 ON T1.apid = T2.src_apid GROUP BY T2.src_apid ORDER BY COUNT(*) DESC LIMIT 1
SELECT "T1"."name", "T1"."city", "T2"."src_apid" FROM "airports" AS "T1" JOIN "routes" AS "T2" ON "T1"."apid" = "T2"."src_apid" GROUP BY "T2"."src_apid" ORDER BY COUNT(*) DESC NULLS LAST LIMIT 1