How to update ms access database table using update and sum() function?

Question

I have Two tables in my access database

• table1(ID,productname,qunatity,remainder)
• table2(ID,productname,sales)

these tables are rela

Answer 1

Perform an update join by getting the SUM() first like

UPDATE a 
SET    a.remainder = x.SaleTotal
FROM   table1 a 
       INNER JOIN (SELECT productname, SUM(sales) AS SaleTotal 
                   FROM TABLE2 GROUP BY productname) x 
       ON a.productname = x.productname;