20.sql

select s_name, s_address from SUPPLIER, NATION where s_suppkey in ( select ps_suppkey from PARTSUPP where ps_partkey in (select p_partkey from PART where p_name like 'green%') and ps_availqty > (select 0.5 * sum(l_quantity) from LINEITEM where l_partkey = ps_partkey and l_suppkey = ps_suppkey and l_shipdate >= date '1993-01-01' and l_shipdate < date '1993-01-01' + interval '1' year)) and s_nationkey = n_nationkey and n_name = 'ALGERIA' order by s_name;