EXPLAIN select c_count, count(*) as custdist from ( select c_custkey, count(o_orderkey) from customer left outer join orders on c_custkey = o_custkey and o_comment not like '%unusual%packages%' group by c_custkey ) as c_orders (c_custkey, c_count) group by c_count order by custdist desc, c_count desc;
                                                     QUERY PLAN                                                      
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 Sort  (cost=1815453.20..1815453.70 rows=200 width=8)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   ->  HashAggregate  (cost=1815443.56..1815445.56 rows=200 width=8)
         Group Key: count(orders.o_orderkey)
         ->  GroupAggregate  (cost=0.86..1792941.80 rows=1500117 width=8)
               Group Key: customer.c_custkey
               ->  Merge Left Join  (cost=0.86..1703692.26 rows=14849675 width=8)
                     Merge Cond: (customer.c_custkey = orders.o_custkey)
                     ->  Index Only Scan using customer_pkey on customer  (cost=0.43..74249.18 rows=1500117 width=4)
                     ->  Index Scan using i_o_custkey on orders  (cost=0.43..1440100.49 rows=14849675 width=8)
                           Filter: ((o_comment)::text !~~ '%unusual%packages%'::text)
(11 rows)