14.sql

select 100.00 * sum(case when p_type like 'PROMO%' then l_extendedprice * (1 - l_discount) else 0 end) / sum(l_extendedprice * (1 - l_discount)) as promo_revenue from LINEITEM, PART where l_partkey = p_partkey and l_shipdate >= date '1996-12-01' and l_shipdate < date '1996-12-01' + interval '1' month;