Question

Here’s my query:

$select d.*, 
count(a.id) as delivered
from `dealerships` as d
left join `assignments` as a on (a.id_dealership = d.id)
group by d.id
order by d.name asc

now this works, but it is counting duplicate leads. when I add a.id_lead to the group by, it messes up everything. There is a column in the assignments table called id_lead and I want the count() (delivered) to count the total of assignments grouped by id_lead, so that it ignores more than 1 row with the same id_lead.

Answer 1

Is this what you mean? :

select d.*, 
count(distinct a.id_lead) as delivered
from `dealerships` as d
left join `assignments` as a on (a.id_dealership = d.id)
group by d.id
order by d.name asc

It’s the same as your query, except that instead of counting the total number of records in a, it will only count the number of distinct non-null values in a.id_lead.

(If that’s not what you mean, then please clarify.)