mysql SELECT LEFT title 20 LEFT author 20 FROM books UNION ALL SELECT

1
2
3
mysql> SELECT LEFT(title,20),LEFT(author,20) FROM books UNION ALL SELECT 'книг нет',LEFT(fio,20) FROM consumer;
mysql> select * from country inner join city on country.Code = city.CountryCode where city.Population > 1000000;
select country.Name, city.Name, city.Population from country inner join city on country.Code = city.CountryCode where city.Population < 1000000;