Write a query to display the product name and unit price for all the products supplied by the Ma Maison company

Question

use subquery only.

Answer 1

Performance wise below is best query. We should avoid table in from clause from which we donot need take any column in select only validate the value we should take that table in subquery

select a.product_id,a.description,b.rate

from product a, order b

where a.product_id=b.product_id

and exists(select 1

from ,company c

where c.company_id= b.company_id

and c.company_name = 'Ma Maison company');

Answer 2

select a.product_id,a.description production_name,b.rate unit_price

from product a, order b

where a.product_id=b.product_id

and exists(select null

from ,company c

where c.company_id= b.company_id

and c.company_name = 'Ma Maison company');

Answer 3

select a.product_id,a.description,b.rate

from product a, order b,company c

where a.product_id=b.product_id

and b.company_id= c.company_id

and c.company_name = 'Ma Maison company';