Add available balance

postgres/queries/categories.sql

@@ -43,9 +43,34 @@ SELECT categories.id, categories.name, category_groups.name as group,
             WHERE categories.id = t_this.category_id 
             AND t_this.date BETWEEN @from_date AND @to_date
         )
-    , 0)::decimal(12,2) as activity
+    , 0)::decimal(12,2) as activity,
+    COALESCE(
+        (
+            SELECT SUM(a_hist.amount)
+            FROM assignments a_hist
+            WHERE categories.id = a_hist.category_id 
+            AND a_hist.date BETWEEN @from_date AND @to_date
+        )
+    ,0)::decimal(12,2) as assigned
+
 FROM categories
 INNER JOIN category_groups ON categories.category_group_id = category_groups.id
 WHERE category_groups.budget_id = @budget_id
 GROUP BY categories.id, categories.name, category_groups.name
-ORDER BY category_groups.name, categories.name;
+ORDER BY category_groups.name, categories.name;
+
+-- name: GetAvailableBalance :one
+SELECT 
+    ((
+        SELECT SUM(transactions.amount)
+        FROM transactions
+        LEFT JOIN categories ON categories.id = transactions.category_id
+        LEFT JOIN budgets ON budgets.income_category_id = categories.id
+        WHERE budgets.id = @budget_id
+    ) - (
+        SELECT SUM(assignments.amount)
+        FROM assignments
+        INNER JOIN categories ON categories.id = assignments.category_id
+        INNER JOIN category_groups ON category_groups.id = categories.category_group_id
+        WHERE category_groups.budget_id = @budget_id
+    ))::decimal(12,2);