traxxx/migrations/20220716223422_random_campaign.js

exports.up = async (knex) => Promise.resolve()
	.then(() => knex.schema.createTable('random_campaign', (table) => {
		table.text('banner_id')
			.references('id')
			.inTable('banners');

		table.text('url');

		table.integer('entity_id')
			.references('id')
			.inTable('entities');

		table.string('affiliate_id')
			.references('id')
			.inTable('affiliates');

		table.integer('parent_id')
			.references('id')
			.inTable('entities');
	}))
	.then(() => knex.raw(`
		ALTER TABLE banners ADD COLUMN ratio numeric GENERATED ALWAYS AS (ROUND(width::decimal/ height::decimal, 2)) STORED;
	`))
	.then(() => knex.raw(`
		DROP FUNCTION IF EXISTS get_random_campaign;
		DROP FUNCTION IF EXISTS banners_ratio;

		CREATE FUNCTION get_random_campaign(min_ratio decimal default 0, max_ratio decimal default 1000.0) RETURNS random_campaign AS $$
			SELECT * FROM (
				SELECT DISTINCT ON (CASE WHEN parent_id IS NOT NULL THEN parent_id ELSE entity_id END)
					banner_id, url, entity_id, affiliate_id, parent_id
				FROM (
					SELECT
						campaigns.*, entities.parent_id as parent_id
					FROM campaigns
					LEFT JOIN entities ON entities.id = campaigns.entity_id
					LEFT JOIN banners ON banners.id = campaigns.banner_id
					WHERE banner_id IS NOT NULL
					AND ratio >= min_ratio
					AND ratio <= max_ratio
					ORDER BY RANDOM()
				) random_campaigns
			) random_banners
			ORDER BY RANDOM()
			LIMIT 1;
		$$ LANGUAGE SQL STABLE;
	`));

exports.down = async (knex) => knex.raw(`
	DROP FUNCTION IF EXISTS get_random_campaign;
	DROP TABLE IF EXISTS random_campaign;

	ALTER TABLE banners DROP COLUMN ratio;

	CREATE FUNCTION banners_ratio(banner banners) RETURNS numeric AS $$
		SELECT ROUND(banner.width::decimal / banner.height::decimal, 2);
	$$ LANGUAGE SQL STABLE;
`);