if i have a prodcut with product no. and each product is made by many parts with parts no.
now i would like to retrieve data to count how many parts to make a product.
in sql, can i count parts no. by each product no. like belows:
select product_no,parts_name,manufacture_date,(select count(*) from item where product_no=p.product_no) as [No. of items] from prodcut p left outer join item i on p.product_no=i.product_no
but i found that the execution time is too long, is it the right way to count no. of item in each product??
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