Why does average not exist "CREATE VIEW clean$\_$data AS

SELECT

product$\_$id$,$

COALESCE$($product$\_$type, 'Unknown'$)$ AS product$\_$type,

COALESCE$($brand$,$ 'Unknown'$)$ AS brand,

COALESCE$($weight$,($SELECT ROUND$($AVG$($weight$),2)$ FROM Products WHERE weight IS NOT NULL$))$ AS weight,

COALESCE$($price$,($SELECT ROUND$($AVG$($price$),2)$ FROM Products WHERE price IS NOT NULL$))$

AS price,

COALESCE$($average$\_$units$\_$sold, $0)$ AS average$\_$units$\_$sold,

COALESCE$($year$\_$added, $2022)$ AS year$\_$added,

COALESCE$($stock$\_$location, 'Unknown'$)$ AS stock$\_$location

FROM Products;"