MySQL се присъединява към една и съща таблица два пъти в една и съща колона с различна стойност, връщаща само последния ред

Опитайте

SELECT i.id,  
       i.address, 
       i.status,
       p.max_date contract_date, 
       p.basis_value contract_price, 
       e.max_date estimate_date, 
       e.basis_value estimate_value
  FROM Instructions i LEFT JOIN
(
    SELECT q1.instruction_id, max_date, basis_value
      FROM Estimates e JOIN
    (
        SELECT instruction_id, MAX(basis_date) max_date
          FROM Estimates
         WHERE basis = 'CustomerEstimate'
         GROUP BY instruction_id
    ) q1 ON e.instruction_id = q1.instruction_id AND e.basis_date = q1.max_date
) e ON i.id = e.instruction_id LEFT JOIN
(
    SELECT q2.instruction_id, max_date, basis_value
      FROM Estimates e JOIN
    (
        SELECT instruction_id, MAX(basis_date) max_date
          FROM Estimates
         WHERE basis = 'ContractPrice'
         GROUP BY instruction_id
    ) q2 ON e.instruction_id = q2.instruction_id AND e.basis_date = q2.max_date
) p ON i.id = p.instruction_id
 

Изход:

Ето SQLPiddle демонстрация.