mysql - Join multiple tables where id may not exist -

i have 2 tables follows:

table_a: id, title table_b: id, table_a_id, status 

i want select total number of entries in table_b each value of table_a, total number of entries in table_b not reference table_a.

for example, let's table_a has values:

{id, title} (1, "value 1") (2, "value 2") (3, "value 3") 

and table_b has following entries

{id, table_a_id, status} (1, 1, 'open') (2, 1, 'closed') (3, -, 'open') (4, 2, 'closed') 

what trying along lines of:

("value 1", 2) ("value 2", 1) ("value 3", 0) (-, 1) 

without nulls, write as:

select table_a.id, table_a.title, count(table_b.id)  table_a      left join table_b on table_a.id = table_b.table_a_id group table_a.id, table_a.title 

however, doesn't give me values entries in table_b not reference table_a. if reverse join, can values table_b, not table_a. how can both in single query?

i'm using sql server, guess it'll work on mysql too. important here coalesce function, and mysql runs same way sql server does.

select coalesce(a.title, '-'), count(b.id) #table_b b left join #table_a on b.table_a_id = a.id group a.title union select a.title, 0 #table_a left join #table_b b  on b.table_a_id = a.id b.id null