How to convert data into this form in SQL :

Input:

I have to Convert data from input to output. where we trying if for id freq is n then create n rows of that id.

Output:

Answer

In Presto, one option uses sequence() and a lateral join to generate the rows:

select t.id, x.value
from mytable t
cross join lateral unnest(sequence(1, t.freq)) as x(value)
order by t.id, x.value