CREATE TABLE "pays" ( `id` INTEGER, `user_id` INTEGER, `pay` TEXT, PRIMARY KEY(`id`) )
CREATE TABLE "users" ( `id` integer, `name` text, PRIMARY KEY(`id`) )

create view if not exists totals as
	select users.name as 'Имя',
	sum(pays.pay) as  'Взнос',
	(select sum(pay) from pays)/(select count(*) from users) as "Средний взнос",
	sum(pays.pay) - (select sum(pay) from pays)/(select count(*) from users) as "Итог"
	from users
	join pays
	on users.id=pays.user_id
	group by name;

	select * from totals;

explain query plan [select...]
explain [select...] 

select name,pay from users,pays where user.id=pays.user_id;

drop table if exists pays_tmp;
create temp table pays_tmp(sum_pay text,avg_pay text);
insert into pays_tmp(sum_pay) values((select sum(pay) from pays));
insert into pays_tmp(avg_pay) values((select sum_pay from pays_tmp)/(select count(*) from users));
SELECT name Имя,
sum(pay) Взнос,
sum(pay) - (select avg_pay from pays_tmp) Итог
FROM users,pays where users.id = pays.user_id
GROUP BY name
union all
select '','Всего: '||(select sum_pay from pays_tmp),
'Среднее: '||((select avg_pay from pays_tmp));

CREATE TABLE pays (id integer PRIMARY KEY , name text, pay numeric NOT NULL, date text DEFAULT (date()))
CREATE TABLE users (name text PRIMARY KEY)
CREATE TRIGGER add_pay AFTER INSERT ON pays 
BEGIN 
 select raise(abort,'Несуществующее имя') 
 where new.name not in (select name from users);
END

select name,sum(pay) from pays
group by name