feat: added the default grouping by month in sum_by_category

Author: Antenaina2002

src/main/resources/migrations/function_expense

@@ -1,14 +1,24 @@
-CREATE OR REPLACE FUNCTION sum_by_category(start_date DATE, end_date DATE)
-RETURNS TABLE(account_id bigint, category_id bigint, total_amount DOUBLE PRECISION) 
+CREATE OR REPLACE FUNCTION sum_by_category(start_date DATE, end_date DATE, interval TEXT = 'month')
+RETURNS TABLE(account_id bigint, category_id bigint, total_amount DOUBLE PRECISION) 
 AS $$
 BEGIN
-  RETURN QUERY
-    SELECT t.id_account, c.id AS category_id, SUM(t.amount) AS total_amount
-    FROM transaction t
-    JOIN category c ON t.category = c.id
-    WHERE t.created_at BETWEEN start_date AND end_date
-    GROUP BY t.id_account, c.id
-    ORDER BY t.id_account, total_amount DESC;
+  IF interval = 'day' THEN
+    RETURN QUERY
+      SELECT t.id_account, c.id AS category_id, SUM(t.amount) AS total_amount
+      FROM transaction t
+      JOIN category c ON t.category = c.id
+      WHERE t.created_at BETWEEN start_date AND end_date
+      GROUP BY t.id_account, DATE(t.created_at)
+      ORDER BY t.id_account, total_amount DESC;
+  ELSE
+    RETURN QUERY
+      SELECT t.id_account, c.id AS category_id, SUM(t.amount) AS total_amount
+      FROM transaction t
+      JOIN category c ON t.category = c.id
+      WHERE t.created_at BETWEEN start_date AND end_date
+      GROUP BY t.id_account, MONTH(t.created_at)
+      ORDER BY t.id_account, total_amount DESC;
+  END IF;
 END;
 $$
-LANGUAGE plpgsql;
+LANGUAGE plpgsql;