Create 02173-longest-winning-streak.sql

Author: leetlab11

Hard/02173-longest-winning-streak.sql

@@ -0,0 +1,23 @@
+-- first, do a rank on all roecords for user, and a rank on each result for each user 
+-- for each result, there will be a streak(count of records)- the differnce between the two ranks will be same for each streak- we'll filter out only streaks where type = Win 
+-- in the final result, pull the max streak for each player in Matches table. If that player is not in cte, then 0
+
+with ranked as
+(select *,
+    row_number() over(partition by player_id order by match_day) as all_rnk,
+    row_number() over(partition by player_id, result order by match_day) as result_rnk
+from Matches),
+
+win_streak_player as
+(select player_id, count(*) as win_streak
+from ranked
+where result = 'Win'
+group by 1, all_rnk - result_rnk)
+
+select m.player_id, ifnull(max(win_streak), 0) as longest_streak
+from Matches m
+left join win_streak_player w
+using(player_id)
+group by 1
+
+-- amazon- 1