Add views with results grouped by month

postgres/schema/202112081529_views-for-months.sql

@@ -0,0 +1,17 @@
+-- +goose Up
+CREATE VIEW transactions_by_month AS 
+        SELECT extract(year from transactions.date) as year, extract(month from transactions.date) as month, transactions.category_id, accounts.budget_id, SUM(amount) as amount
+        FROM transactions
+        INNER JOIN accounts ON accounts.id = transactions.account_id
+        GROUP BY extract(year from transactions.date), extract(month from transactions.date), transactions.category_id, accounts.budget_id;
+
+CREATE VIEW assignments_by_month AS 
+        SELECT extract(year from assignments.date) as year, extract(month from assignments.date) as month, assignments.category_id, category_groups.budget_id, SUM(amount) as amount
+        FROM assignments
+        INNER JOIN categories ON categories.id = assignments.category_id
+        INNER JOIN category_groups ON categories.category_group_id = category_groups.id
+        GROUP BY extract(year from assignments.date), extract(month from assignments.date), assignments.category_id, category_groups.budget_id;
+
+-- +goose Down
+DROP VIEW transactions_by_month;
+DROP VIEW assignments_by_month;