是什么导致了 from 选择中的语法？

Question

为什么会有 "from": 语法错误？

select
l_year,
sum(case
when nation = 'UNITED STATES' then volume
else 0
end) / sum(volume) as mkt_share
from
(
    select
        extract(year from l_shipdate) as l_year,
        l_extendedprice * (1 - l_discount) as volume,
         n2.n_name as nation

我猜底线会导致错误

    from 
        part,
        supplier,
        lineitem,
        orders,
        customer,
        nation n1,
        nation n2,
        region
    where
    p_partkey = l_partkey
    and s_suppkey = l_suppkey
    and l_orderkey = o_orderkey
    and o_custkey = c_custkey
    and c_nationkey = n1.n_nationkey
    and n1.n_regionkey = r_regionkey
    and r_name = 'ASIA'
    and s_nationkey = n2.n_nationkey
    and l_shipdate between '1997-01-01' and '1997-12-31'
) as all_nations
group by l_year
order by l_year;