Error code 1248, SQL state 42000: Every derived table must have its own alias

Question

I am running this query on MySQL.

Select Vendor, sum(Rate) as Rate
from (select case Vendor when 'NSN' then 'Nokia' else Vendor end as Vendor, Rate
from (  Select vendor ,(count(1) )*100/(Select count(id_incident)from incident where open_time between '2015-01-01'and'2015-01-30') as Rate from incident  where open_time between '2015-01-01'and'2015-01-30'group by upper (vendor) )) as y group by vendor;   

and it is giving this error:

Error code 1248, SQL state 42000: Every derived table must have its own alias".

what's the problem?

Answer 1

You forgot to give the inner subquery an alias. I chose x

Select Vendor, sum(Rate) as Rate
from 
(
   select case Vendor when 'NSN' then 'Nokia' else Vendor end as Vendor, Rate
   from 
   (  
     Select vendor ,(count(1) )*100/(Select count(id_incident)from incident where open_time between '2015-01-01'and'2015-01-30') as Rate 
     from incident  
     where open_time between '2015-01-01'and'2015-01-30'
     group by upper (vendor) 
   ) as x
) as y 
group by vendor;