Create premier-league-table-ranking-ii.sql

Author: kamyu104

MySQL/premier-league-table-ranking-ii.sql

@@ -0,0 +1,29 @@
+# Time:  O(nlogn)
+# Space: O(n)
+
+# window function
+WITH teams_points_cte AS (
+    SELECT team_id,
+           team_name,
+           wins * 3 + draws * 1 + losses * 0 AS points
+    FROM TeamStats
+), teams_ranks_cte AS (
+    SELECT team_id,
+        team_name,
+        points,
+        RANK() OVER (ORDER BY points DESC) AS position
+    FROM teams_points_cte
+), team_count_cte as  (
+    SELECT COUNT(*) as num_teams
+    FROM TeamStats
+)
+
+SELECT team_name,
+       points,
+       position,
+       CASE WHEN position <= CEIL(num_teams * 0.33) THEN "Tier 1"
+            WHEN position <= CEIL(num_teams * 0.66) THEN "Tier 2"
+            ELSE "Tier 3"
+       END AS tier
+FROM teams_ranks_cte, team_count_cte
+ORDER BY 2 DESC, 1;