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- insert into family (family_name) values (
- 'Синицевые'
- );
- insert into family (family_name, description) values (
- 'Врановые',
- 'Семейство птиц, включающее воронов, грачей, сорок и других'
- ), (
- 'Дроздовые',
- 'Семейство певчих птиц, включающее дроздов, дрозд-рябинников и других'
- );
- insert into genus (genus_name, family_id) values (
- 'Синица',
- 1
- ), (
- 'Гаичка',
- 1
- ), (
- 'Ворон',
- 2
- ), (
- 'Сорока',
- 2
- ), (
- 'Дрозд',
- 3
- );
- table genus;
- select genus_name from genus;
- select genus_name, genus_id from genus;
- select genus_name as bird_genus, genus_id from genus;
- select genus_name as bird_genus, genus_id from public.genus;
-
- 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='Дроздовые' and family_name='Синицевые';
- select * from family where family_name like '%а%' or family_name like '%с%';
- select * from family;
- -- Используем функцию coalesce для полей со значением null
- select family_id, family_name, coalesce(description, 'не заполнено') description from family;
- select * from family where description is null or family_name like '%Д%';
- -- Временная таблица для сортировка
- create temp table author_tmp(
- author_id bigint generated always as identity primary key,
- first_name varchar(150) not null,
- last_name varchar(150) not null
- );
- insert into author_tmp (first_name, last_name) values
- ('Михаил', 'Шишкин'),
- ('Михаил', 'Веллер'),
- ('Михаил', 'Шолохов'),
- ('Михаил', 'Зощенко'),
- ('Михаил', 'Булгаков'),
- ('Александр', 'Беляев'),
- ('Александр', 'Пушкин'),
- ('Лусиану', 'Рамальо');
- select * from author_tmp;
- select * from author_tmp order by first_name;
- select * from family order by family_id desc;
- select * from family order by description nulls first;
- select * from family;
- select family_name from family where family_name like 'Д%' order by family_name;
- select * from (
- values (2, 3), (3, 20), (2, 4), (1, 20), (3, 4), (1, 19)
- ) as something(a, b)
- select * from (
- values (2, 3), (3, 20), (2, 4), (1, 20), (3, 4), (1, 19)
- ) as something(a, b)
- order by a, b;
- select * from (
- values (3, 20), (2, 4), (1, 20), (3, 4), (3, null), (1, 19), (2, 1), (2, null)
- ) as something(a, b)
- order by a, b desc nulls last;
- table genus;
- table species;
- select * from species
- order by species_name, description
- limit 10 offset 10;
- select species_id, species_name, primary_color from species where primary_color ilike '%бел%'
- order by species_name
- limit 5;
- select 'sadfs' || 'sadfasdf' || now() as message;
- drop schema if exists tests cascade;
- create schema tests;
- select format('Птичка: %s', species_name) as "птичка" from species
- order by species_name;
- update species
- set species_name='Древесный дрозд'
- where species_name='Дрозд лесной'
- update species
- set species_name='Дрозд лесной'
- where species_name='Древесный дрозд'
- -- Создание схемы
- drop schema if exists birds cascade;
- create schema birds;
- table genus;
- select genus_id as crows_id from genus where genus_name='Ворон';
- select * from species;
- create table crows as
- select * from species where genus_id=(select genus_id from genus where genus_name='Ворон');
- table crows;
- truncate table crows;
- drop table crows;
- create table smth (a int);
- insert into smth(a) values (1), (2), (3);
- table smth;
- update smth set a=a*2;
- select pg_column_size('привеееет');
- create temp table game_genre (
- genre_id bigint primary key,
- genre_name text
- );
- create temp table game (
- game_id int generated always as identity primary key,
- genre_id int not null references game_genre(genre_id)
- );
- insert into game_genre(genre_id, genre_name) values (1234567890123456789, 'шутер');
- insert into game(genre_id) values (1234567890123456789);
- comment on table family is 'Семейство птиц';
- comment on column family.family_id is 'Уникальный идентификатор семейства';
- comment on column family.family_name is 'Название семейства';
- comment on column family.description is 'Описание семейства';
- comment on table genus is 'Род птиц';
- comment on column genus.genus_id is 'Уникальный идентификатор рода';
- comment on column genus.genus_name is 'Название рода';
- comment on column genus.family_id is 'Ссылка на семейство';
- comment on column genus.description is 'Описание рода';
- comment on table species is 'Вид птиц';
- comment on column species.species_id is 'Уникальный идентификатор вида';
- comment on column species.species_name is 'Название вида';
- comment on column species.genus_id is 'Ссылка на род';
- comment on column species.description is 'Описание вида';
- comment on column species.average_length is 'Средняя длина в см';
- comment on column species.average_weight is 'Средний вес в г';
- comment on column species.primary_color is 'Цвет оперения';
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