How many different furniture items are there?
select count(distinct furniture_id) from furniture
How many are sold by manufacturers in our records?
select count(distinct furniture_id) from furniture where furniture_id in (select furniture_id from furniture_manufacte)
Which furniture names are not in our records?
select name from furniture where furniture_id not in (select furniture_id from furniture_manufacte)
Also show their market rates.
select market_rate, name from furniture where furniture_id not in (select furniture_id from furniture_manufacte)