USE tpch1;
select count(n_nationkey)
from nation, customer, orders, lineitem
where n_nationkey = c_nationkey and
c_custkey = o_custkey and
o_orderkey = l_orderkey and
l_orderkey <= 10000;
count(n_nationkey)
9965
select count(n_nationkey)
from nation, customer, orders, lineitem
where c_custkey = o_custkey and
o_orderkey = l_orderkey and
n_nationkey = c_nationkey and 
l_orderkey <= 10000;
count(n_nationkey)
9965