s:([s:`s1`s2`s3`s4`s5]
name:`smith`jones`blake`clark`adams;
status:20 10 30 20 30;
city:`london`paris`paris`london`athens)
p:([p:`p1`p2`p3`p4`p5`p6]
name:`nut`bolt`screw`screw`cam`cog;
color:`red`green`blue`red`blue`red;
weight:12 17 17 14 12 19;
city:`london`paris`rome`london`paris`london)
sp:([]
s:`s$`s1`s1`s1`s1`s4`s1`s2`s2`s3`s4`s4`s1;/ fkey
p:`p$`p1`p2`p3`p4`p5`p6`p1`p2`p2`p2`p4`p5;/ fkey
qty:300 200 400 200 100 100 300 400 200 200 300 400)
select distinct p,s.city from sp
/s select distinct sp.p,s.city from sp,s where sp.s=s.s
select sum qty by p.color from sp
/s select p.color,sum(sp.qty) from sp,p where sp.p=p.p group by p.color order by color
select from sp where s.city=p.city
/s select sp.s,sp.p,sp.qty from s,p,sp where sp.s=s.s and sp.p=p.p and p.city=s.city