l1 POLYGON( (3 7, 5 7, 5 4, 3 4, 3 7 ) )
l2 POLYGON( (6 2, 11 2, 11 0, 6 0, 6 2) )
l3 POLYGON( (7 8 ,11 6 ,7 6 , 7 8 ) )
l4 POLYGON( (4 9, 7 9, 7 7, 4 7, 4 9 ) )
l5 POLYGON( (14 7, 15 8, 18 8, 19 7 , 19 6,18 5 , 15 5, 14 6 , 14 7 ) )

Q1 POLYGON( (2 9, 11 9 ,11 2,2 2, 2 9 ) )
Q2 POLYGON( (12 7, 14 11, 18 11, 20 7, 18 3, 14 3, 12 7 ) )

Questao 1:
SELECT r2.id
FROM exemplo_lotes r1, exemplo_lotes r2
WHERE touches (r1.geom, r2.geom)
AND ( r1.id = 4 )

Questao 2:  
SELECT r2.id
FROM exemplo_quadras q1, exemplo_lotes r2
WHERE within ( r2.geom , q1.geom )
AND ( q1.id = 1 )

Questao 3:
insert into terceira_questao VALUES (1, 'resposta' , (SELECT (geomunion(r2.geom)) as geom
FROM exemplo_quadras q1, exemplo_lotes r2
WHERE within ( r2.geom , q1.geom )
AND ( q1.id = 1 )) )   

Questao 4:
insert into exemplo_quadras_lotes    SELECT r2.id as id , 'Lote' , r2.geom as geom
FROM  exemplo_lotes r2 , (select geomunion(q1.geom) as geo from exemplo_quadras q1) q2
WHERE not contains (   q2.geo , r2.geom  ) 

insert into exemplo_quadras_lotes    SELECT q.id as id , 'Quadra' , q.geom as geom
FROM  exemplo_quadras q