Number of forks

select base_projects.base_project_id, base_projects.name as base_project_name, 
base_projects.url as base_project_url, count(forks.id) as num_forks from 
(select * from projects) as forks
right join
(select id as base_project_id, name, url from projects
where forked_from is null) as base_projects
on forks.forked_from = base_projects.base_project_id
group by base_projects.base_project_id

GHData