MySQL 5.6

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create table brand( id_brand int, brand_car_name varchar(50) ) 
create table vehicule( id int, id_model int )
create table model( id int, id_brand int, id_model int )
insert into brand values(1,'Mercedes'),(2,'Volvo')

Records: 2  Duplicates: 0  Warnings: 0


insert into vehicule values(1,1)
insert into model values(1,1,1)
SELECT b.brand_car_name, SUM( IFNULL(SIGN(v.ID_MODEL),0) ) as BRAND_COUNT
  FROM brand b
  LEFT JOIN model mo ON mo.ID_BRAND = b.id_brand
  LEFT JOIN vehicule v ON v.ID_MODEL = mo.ID_MODEL
 GROUP BY b.brand_car_name


brand_car_name
BRAND_COUNT


Mercedes
1

Volvo
0