Question

I am attempting to join two tables to my query and count the number of matching rows from each of the joins. It seems to come back with the wrong result though. It seems to be doubling the results. Here is the query

SELECT *, COUNT(car_id) AS numCars, COUNT(van_id) AS numVans 
            FROM company_branch
            LEFT JOIN car ON car_branchid = company_branch_id
            LEFT JOIN van ON van_branchid = company_branch_id
            WHERE company_branch_userid = 1

            GROUP BY company_branch_id, 
            ORDER BY company_branch_active DESC, company_branch_name ASC

Answer 1

I’m assuming that car_id is the primary key on the car table and van_id is the primary key on the van table. In that case, use DISTINCT to get the counts in each group individually. Try this:

SELECT *, COUNT(DISTINCT car_id) AS numCars, COUNT(DISTINCT van_id) AS numVans 
        FROM company_branch
        LEFT JOIN car ON car_branchid = company_branch_id
        LEFT JOIN van ON van_branchid = company_branch_id
        WHERE company_branch_userid = 1

        GROUP BY company_branch_id, 
        ORDER BY company_branch_active DESC, company_branch_name ASC