finish Monthly Transactions I

Author: babebp

SQL/Monthly_Transactions_I.sql

@@ -0,0 +1,19 @@
+-- Problem : https://leetcode.com/problems/monthly-transactions-i/description/?envType=study-plan-v2&envId=top-sql-50
+
+SELECT TO_CHAR(trans_date, 'YYYY-MM') as month, 
+    country, count(*) as trans_count, 
+    SUM(
+        CASE
+            WHEN state = 'approved' THEN 1
+            ELSE 0
+        END
+    ) as approved_count,
+    SUM(amount) as trans_total_amount,
+    SUM(
+        CASE
+            WHEN state = 'approved' THEN amount
+            ELSE 0
+        END
+    ) as approved_total_amount
+FROM Transactions
+GROUP BY month, country;