obsidian/hardcore web development/11. SQL/quiz_1.sql

-- -----------------------------------------------------------------
-- Задания

-- -----------------------------------------------------------------
-- 11.16 Выборка данных из других источников

-- Выборка из подзапроса
select genus_name from (
    select * from genus
);


-- Выборка анбора дат с интервалом в 2 месяца
select date
from generate_series('2020-01-01'::date,
                    '2024-06-01'::date,
                    '2 month'::interval) date;

--
select * from (values
    ('The Shawshank Redemption', 9.3, 1994),
    ('The Godfather', 9.2, 1972),
    ('The Dark Knight', 9.1, 2008),
    ('Inception', 8.8, 2010)
) t(movie, imdb_rating, year);


-- -----------------------------------------------------------------
-- 11.18 Фильтрация данных

table family;

select * from family where family_name='Дроздовые';

select * from family where family_name='Дроздовые' or family_name='Синицевые';

select * from family where family_name in ('Дроздовые', 'Синицевые');

select * from family where family_name like '%а%'; 

select * from family where family_name like '%а%' or family_name like '%с%';

select * from family where family_name ilike '%а%';


-- -----------------------------------------------------------------
-- 11.19 Особое значение NULL, coalesce

select family_id, family_name, coalesce(description, 'не заполнено') as description from family;

select * from family where description is null;

select * from family where description is null or family_name like '%Д%';


-- -----------------------------------------------------------------
-- 11.20 Сортировка данных

select * from family order by family_id;

select * from family order by description nulls first;

select * from family order by sescription nulls last;

select family_name from family where family_name like 'Д%' order by family_name; 

-- -----------------------------------------------------------------
-- 11.21 Ограничение количества результатов запроса

table species;

select * from species order by species_name, description
limit 10 offset 10;

select species_id, species_name from species where primary_color ilike '%бел%'
order by species_name
limit 5;