Create monthly-transactions-i.sql

Author: kamyu104

MySQL/monthly-transactions-i.sql

@@ -0,0 +1,13 @@
+# Time:  O(n)
+# Space: O(n)
+
+SELECT Date_format(trans_date, '%Y-%m')       AS month, 
+       country, 
+       Count(id)                              AS trans_count, 
+       Count(IF(state = 'approved', 1, NULL)) AS approved_count, 
+       SUM(amount)                            AS trans_total_amount, 
+       SUM(IF(state = 'approved', amount, 0)) AS approved_total_amount 
+FROM   transactions 
+GROUP  BY Date_format(trans_date, '%Y-%m'), 
+          country 
+ORDER BY NULL