@Hubert Dudek​ , SQL Code:

select 
  c.client_id
  ,c.birth_date
  ,a.contract_prod_id
  ,a.contract_id
  ,a.contract_number
  ,a.mig_contract_number
  ,a.contract_amount
  ,a.ref_number
  ,a.status
  ,p.product_type
from clients c
left join contracts a
on a.contract_client_id = c.client_id
left join products p
on p.product_id = a.product_id

Data sample: