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@@ -210,3 +210,98 @@ select email from employees
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where extract('month' from birthday)=4
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order by email;
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+-- -----------------------------------------------------------------
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+-- 11.31 Работа с массивами
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+
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+drop table if exists log;
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+table log;
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+
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+create temp table log (
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+ log_id bigint generated always as identity,
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+ created_at timestamp not null default current_timestamp,
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+ messages text not null
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+);
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+
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+insert into log (created_at, messages) values(
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+ '2024-08-01 00:47:28.821', 'кажется, всё пропало|или нет, пытаемся восстановить связь|нет, точно всё пропало'
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+);
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+
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+insert into log (created_at, messages) values(
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+ '2024-08-01 01:06:21.581', 'id=128|ничоси, опять всё сломалось, никогда такого не было и вот опять'
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+);
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+
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+select log_id, created_at, (string_to_array(messages, '|'))
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+[array_length(string_to_array(messages, '|'), 1)] as last_message
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+from log;
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+
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+select log_id, created_at,
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+ split_part(messages, '|', array_length(string_to_array(messages, '|'), 1)) as last_message
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+from log;
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+
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+select log_id, created_at, split_part(messages, '|', -1) as last_message from log;
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+
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+--
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+select unnest(string_to_array(messages, '|')) as messages from log;
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+
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+select int_array from some_entity where 777=any(int_array);
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+
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+select unnest(string_to_array(messages, '|')) from log;
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+
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+select unnest as messages from (select unnest(string_to_array(messages, '|')) from log)
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+where unnest like '%всё%';
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+
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+-- более короткое решение
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+select t.* from (
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+ select unnest(string_to_array(messages, '|') messages
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+ from log
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+) t where t.messages '%всё%';
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+
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+-- -----------------------------------------------------------------
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+-- 11.33 Работа с JSON и JSONB
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+
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+drop table if exists book_json;
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+
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+create temp table book_json (
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+ book_id bigint generated always as identity primary key,
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+ data jsonb not null
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+);
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+
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+-- Данные в поле data (jsonb) могут различаться
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+insert into book_json (data) values
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+ ('{"name": null}'),
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+ ('{"name": ""}'),
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+ ('{"name": "Тихий Дон"}'),
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+ ('{"name": 777}'),
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+ ('{}');
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+
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+table book_json;
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+
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+select book_id, data from book_json where data ? 'name';
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+
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+select book_id, data from book_json where data->>'name' is not null;
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+
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+select book_id, data from book_json where length(data->>'name') > 0;
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+
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+-- или вот такой вариант
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+select * from book_json
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+where data->>'name' is not null and data->>'name' != '';
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+
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+-- Создание таблицы с ограничениями по jsonb
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+create table book_json(
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+ book_id bigint generated always as identity primary key,
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+ data jsonb not null check (
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+ data->>'name' is not null and
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+ data->>'pages' is not null and
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+ (data->>'pages')::int > 0
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+ )
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+);
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+
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+
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+
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+
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unknown