Create 1369-get-the-second-most-recent-activity.sql

Author: everthis

1369-get-the-second-most-recent-activity.sql

@@ -0,0 +1,14 @@
+# Write your MySQL query statement below
+SELECT * 
+FROM UserActivity 
+GROUP BY username 
+HAVING COUNT(*) = 1
+
+UNION ALL
+
+SELECT u1.*
+FROM UserActivity u1 
+LEFT JOIN UserActivity u2 
+    ON u1.username = u2.username AND u1.endDate < u2.endDate
+GROUP BY u1.username, u1.endDate
+HAVING COUNT(u2.endDate) = 1;