mysql: add weather-observation-station-4

6 years ago · c66d0a58c8
parent 340152c71a
commit c66d0a58c8
1 changed files with 2 additions and 0 deletions
--- a/mysql/weather-observation-station-4/solution.sql
+++ b/mysql/weather-observation-station-4/solution.sql
@ -0,0 +1,2 @@
+SELECT COUNT(CITY) - COUNT(DISTINCT CITY)
+FROM STATION