text: -- file:join.sql ln:736 expect:true
  select c.name, ss.code, ss.b_cnt, ss.const
  from c left join
    (select a.code, coalesce(b_grp.cnt, 0) as b_cnt, -1 as const
     from a left join
       (select count(1) as cnt, b.a from b group by b.a) as b_grp
       on a.code = b_grp.a
    ) as ss
    on (c.a = ss.code)
  order by c.name
  