sql - subquery select when group by is null -

i've got query cannot figure out.

select (   select count(bar.id)   bar   foo.some_id = bar.some_id   ) num_bar   foo   group some_id

if foo looks this:

id|some_id ---------- 1 |null 2 |apple 3 |orange

and bar looks this

id|some_id ---------- 1 |null 2 |apple 3 |orange 4 |null 5 |apple 6 |orange

i expect return:

num_bar ------- 2 2 2

howerver, count on null grouping returns 0 each time.

what proper way account clause when group null?

sql aggregate functions , comparisons may ignore null values in computation

what might want give value , interpret nulls accordingly. in below query, asking query interpret null values -1.

select (  select count(bar.id)  bar  isnull(foo.some_id, -1) = isnull(bar.some_id,-1) ) num_bar foo group isnull(some_id,-1)

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