SELECT
    COUNT(datid) AS CURRENT,
    (
        SELECT
            setting AS mc
        FROM
            pg_settings
        WHERE
            name = 'max_connections') AS mc,
    d.datname
FROM
    pg_database d
    LEFT JOIN pg_stat_activity s ON (s.datid = d.oid)
GROUP BY
    2,
    3
ORDER BY
    datname
;