Sqlite - efficient select count query -

i have table in database select on:

select * tablea; 

i want append column true or false if there's related column in anther table. can this:

select *, (select count(id) > 0 tableb id = tablea.id) tablea; 

but don't want have count every row in tableb work out ineffient. want exists check instead of count.

how replace count exists?

thanks!

by using left join

select a.*, b.id not null condition_check tablea left join tableb b on a.id = b.id