Arbre algébrique des requetes complexes (corrélées)

Bonsoir à tous ;

je travail sur des requêtes imbriquées complexes et je dois créer leurs arbres algébriques, existe ils des liens précises qui s’intéressent sur ce sujet ????

j'ai analyser ces requêtes mais lorsque je l’exécutent leurs résultats sont faussent, merci de m'aider à corrigées.

requête Q20 :

  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 'bisque%' ) 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 '1994-01-01' and l_shipdate < date '1994-01-01' + interval '1' year ) ) and s_nationkey = n_nationkey and n_name = 'CANADA' order by s_name;

requête Q18 :

  select c_name, c_custkey, o_orderkey, o_orderdate, o_totalprice, sum(l_quantity) from customer, orders, lineitem l, ( select l_orderkey from lineitem group by l_orderkey having sum(l_quantity) > 1 )l1 where o_orderkey =l1.l_orderkey  and c_custkey = o_custkey and o_orderkey = l.l_orderkey group by c_name, c_custkey, o_orderkey, o_orderdate, o_totalprice order by o_totalprice desc, o_orderdate ;

requête Q15

 select s_suppkey, s_name, s_address, s_phone, total_revenue from supplier, ( select l_suppkey supplier_no, sum(l_extendedprice * (1 - l_discount))total_revenue from lineitem where l_shipdate >= date '1995-02-01' and l_shipdate < date '1995-02-01' + interval '3' month group by l_suppkey ) revenue0  where s_suppkey = supplier_no and total_revenue = ( select max(total_revenue)  from ( select l_suppkey supplier_no, sum(l_extendedprice * (1 - l_discount))total_revenue from lineitem where l_shipdate >= date '1995-02-01' and l_shipdate < date '1995-02-01' + interval '3' month group by l_suppkey ) revenue0 ) order by s_suppkey;