Update Number of transactions per visit.sql

Author: mrinal1704

Hard/Number of transactions per visit.sql

@@ -83,31 +83,38 @@
 -- * For transactions_count >= 4, No customers visited the bank and did more than three transactions so we will stop at transactions_count = 3
 
 -- Solution
-with recursive t1 as(
-(select visit_date, coalesce(num_visits,0) as num_visits, coalesce(num_trans,0) as num_trans
-from
-(select visit_date, user_id, count(*) as num_visits
-from visits
-group by 1, 2) a
-left join
-(select transaction_date, user_id, count(*) as num_trans
-from transactions
-group by 1, 2) b
-on a.visit_date = b.transaction_date and a.user_id = b.user_id)),
+WITH RECURSIVE t1 AS(
+                    SELECT visit_date,
+                           COALESCE(num_visits,0) as num_visits,
+                           COALESCE(num_trans,0) as num_trans
+                    FROM ((
+                          SELECT visit_date, user_id, COUNT(*) as num_visits
+                          FROM visits
+                          GROUP BY 1, 2) AS a
+                         LEFT JOIN
+                          (
+                           SELECT transaction_date,
+                                 user_id,
+                                 count(*) as num_trans
+                            FROM transactions
+                          GROUP BY 1, 2) AS b
+                         ON a.visit_date = b.transaction_date and a.user_id = b.user_id)
+                      ),
 
-t2 as(
-select max(num_trans) as trans
-from t1
-union all
-select trans-1 from t2
-where trans>=1
-)
+              t2 AS (
+                      SELECT MAX(num_trans) as trans
+                        FROM t1
+                      UNION ALL
+                      SELECT trans-1 
+                        FROM t2
+                      WHERE trans >= 1)
 
-select trans as transactions_count, coalesce(visits_count,0) as visits_count
-from t2 left join
-(select num_trans as transactions_count, coalesce(count(*),0) as visits_count
-from t1 
-group by 1
-order by 1) a
-on a.transactions_count = t2.trans
-order by 1
+SELECT trans as transactions_count, 
+       COALESCE(visits_count,0) as visits_count
+  FROM t2 LEFT JOIN (
+                    SELECT num_trans as transactions_count, COALESCE(COUNT(*),0) as visits_count
+                    FROM t1 
+                    GROUP BY 1
+                    ORDER BY 1) AS a
+ON a.transactions_count = t2.trans
+ORDER BY 1