uso de left join y sum

[cacr]

Cómo ves esto?

Código:

SELECT t1.estado, t2.campo 
FROM (SELECT est_002 AS estado, reg_001, est_001
	FROM public.estado 
	WHERE reg_001 = '06') AS t1
LEFT JOIN (SELECT sum(agri04_005) AS campo,reg_001, est_001
	FROM agri04 
	WHERE reg_001 = '06' AND agri04_001 = '2005'
	GROUP BY reg_001, est_001) AS t2
ON (t1.reg_001=t2.reg_001 AND t1.est_001=t2.est_001)

Lo lancé y me hizo algo, que se parece a lo que busco