It would be something like this on your model:
def self.pending_count
where(status: 0).count
end
def self.in_progress_count
where(status: 1).count
end
def self.finished_count
where(status: 2).count
end
Then you can just call Model.pending_count
(or the other methods) wherever you need it.
solved How to find out the number of records in a table? [closed]