Median of numbers

create Table numbers (number int,frequency int);

insert into numbers values (1,2);

insert into numbers values (4,1);

insert into numbers values (6,2);

insert into numbers values (9,1); 

with cte2 as(

select n.*,

sum(frequency) over (order by number) as acc_sum,

sum(n.frequency) over() as sum_freq from numbers n

)

select avg(c2.number) from cte2 c2

where c2.acc_sum between sum_freq/2 and (sum_freq/2)+c2.frequency;