syntax error

[vaaibhavmohan]

select A.country,count(A.CustomerID) as N
from 
     (select country,Count(CustomerID) as N1 from customers group by country) as A
left join 
    (select country,Count(CustomerID) as N2 from customers group by country) as B 
     on A.N1=B.N2

 

the error:it is not reading A.customerid 

[Ingolme]

You did not select CustomerID from table A, so you cannot access it. Perhaps you actually want to select N1.

[Sherin]

Try updating the code like this :

select A.country, count(A.N1) as N
from 
     (select country,Count(CustomerID) as N1 from customers group by country) as A
left join 
    (select country,Count(CustomerID) as N2 from customers group by country) as B 
     on A.N1=B.N2 group by A.Country