dsageranges

SELECT ageranges.datasetid,

    min(ageranges.younger) AS younger,

    max(ageranges.older) AS older,

    ageranges.agetypeid

   FROM ( SELECT ds.datasetid,

                CASE

                    WHEN (ages.ageyounger IS NULL) THEN ages.age

                    ELSE ages.ageyounger

                END AS younger,

                CASE

                    WHEN (ages.ageolder IS NULL) THEN ages.age

                    ELSE ages.ageolder

                END AS older,

            chrons.agetypeid

           FROM (((ndb.samples samples

             LEFT JOIN ndb.datasets ds ON ((samples.datasetid = ds.datasetid)))

             LEFT JOIN ndb.sampleages ages ON ((ages.sampleid = samples.sampleid)))

             LEFT JOIN ndb.chronologies chrons ON ((ages.chronologyid = chrons.chronologyid)))

          WHERE (chrons.isdefault = (1)::boolean)) ageranges

  GROUP BY ageranges.datasetid, ageranges.agetypeid;