Create game-play-analysis-iii.sql

Author: kamyu104

MySQL/game-play-analysis-iii.sql

@@ -0,0 +1,12 @@
+# Time:  O(nlogn)
+# Space: O(n)
+
+SELECT player_id, 
+       event_date, 
+       @accum := games_played + ( @prev = ( @prev := player_id ) ) * @accum 
+       games_played_so_far 
+FROM   activity, 
+       (SELECT @accum := 0, 
+               @prev := -1) init 
+ORDER  BY player_id, 
+          event_date