Join results using group by clause

Question

How do i join the below 2 queries Query 1

select phn,count(*) from table 1 
group by phn
having count(*)>20 

with the above result i need to join table 2 to get ids

Query 2

select count(distinct id) from table 2 
where (result_of_query1).phn=table 2.phn

Answer 1

You can join as follows:

select count(distinct id)
from table2 t2
inner join (
    select phn
    from table1 
    group by phn
    having count(*) > 20 
) t1 on t1.phn = t2.phn