START TRANSACTION;
auto commit mode: off
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 '1994-02-01'
	and l_shipdate < date '1994-02-01' + interval '1' month;
+-------------------------------------------+
| promo_revenue                             |
+===========================================+
|                                      null |
+-------------------------------------------+
1 tuple
COMMIT;
auto commit mode: on