select * from users

select id, name, country from users
order by name;

select id, name, country, created_at from users 
where country = 'KZ'
order by created_at desc;

select id, name from users 
where email is null;

select id, name from users 
where email is not null;

update users 
set email = 'alice@mail.com'
where name = 'Alice';     -- в моей таблице ни у кого нет email, добавил чтобы посмотреть.

select id, name, UPPER(email) as email_upper from users;

select id, name, LOWER(email) as email_lower from users 
where email is not null;

select id, name, created_at from users 
where created_at > '2024-01-11'
order by created_at desc 
limit 2;