mysql: add weather-observation-station-5

mysql/weather-observation-station-5/solution.sql

@@ -0,0 +1,9 @@
+SELECT CITY, LENGTH(CITY)
+FROM STATION
+ORDER BY LENGTH(CITY) ASC, CITY ASC
+LIMIT 1;
+
+SELECT CITY, LENGTH(CITY)
+FROM STATION
+ORDER BY LENGTH(CITY) DESC, CITY ASC
+LIMIT 1;