SELECT join1.*,
	plan_gestion.pg_nom AS plan_gestion
FROM (SELECT cen_habitats.*,
	sites.libl_site AS nom_site
	FROM spatial.cen_habitats
	JOIN sites
	ON cen_habitats.ref_cod_site=sites.code_site) join1
LEFT JOIN plan_gestion
ON join1.ref_pg=plan_gestion.id_pg
