update window func

avysokih/postgresql/window functions/win_func_tasks.sql

@@ -44,9 +44,13 @@ order by category;
 (`price - next_price`)
 */
 
-select name, category, price, lead(price) over(partition by category order by price) as next_price, 
-price - lead(price) over(partition by category order by price) as diff
-from products_extended;
+with t as(
+select name, category, price,
+lead(price) over (partition by category order by price) as next_price
+from products_extended)
+select name, category, price, next_price,
+price - next_price as diff
+from t order by category;
 
 /*
 Задача 3:
@@ -71,10 +75,12 @@ from products_extended;
 
 */
 
-select  category, name, price, 
-round(avg(price) over (partition by category), 1) as avg_price,
-price > avg(price) over (partition by category) as is_above_avg
-from products_extended;
-
 
+with t as(
+select category, name, price,
+round(avg(price) over (partition by category), 1) as avg_price
+from products_extended)
+select category, name, price, avg_price,
+price > avg_price as is_above_avg
+from t order by category;