SELECT `a`.`name` AS `author_name`, `b`.`name` AS `book_name`
FROM (
SELECT `author_id`, `name`,
ROW_NUMBER() OVER (PARTITION BY `author_id` ORDER BY `id` DESC) AS `row`
FROM `books`
) AS `b`
JOIN `authors` AS `a`
ON `b`.`row` < 6 AND `a`.`id` = `b`.`author_id`
WHERE `a`.`id` IN (список id)
ORDER BY `a`.`name`, `b`.`name`VARCHAR(500)For column values less than 8KB in size, use binary VARCHAR instead of BLOB. The GROUP BY and ORDER BY clauses can generate temporary tables, and these temporary tables can use the MEMORY storage engine if the original table does not contain any BLOB columns.
SELECT `n`.*
FROM `course` AS `n`
INNER JOIN (
SELECT `currency`, MAX(`created_at`) AS `created_at`
FROM `course`
GROUP BY `currency`
) AS `max` USING (`currency`, `created_at`);SELECT `e`.`id`, `e`.`name` as `event_name`, `e`.`country_id`, `e`.`description`,
`c`.`name` as `country_name`, `l`.`links`, `i`.`images`
FROM `events` AS `e`
JOIN `countries` AS `c`
ON `c`.`id` = `e`.`country_id`
LEFT JOIN (
SELECT `event_id`, GROUP_CONCAT(`link`) AS `links`
FROM `links`
GROUP BY `event_id`
) AS `l`
ON `l`.`event_id` = `e`.`id`
LEFT JOIN (
SELECT `event_id`, GROUP_CONCAT(`name`) AS `images`
FROM `images`
GROUP BY `event_id`
) AS `i`
ON `i`.`event_id` = `e`.`id`
ORDER BY `e`.`id` DESC
LIMIT :start, :maxSELECT `address`, GROUP_CONCAT(`date`) AS `dates`, COUNT(*)
FROM (
SELECT DISTINCT `address`, DATE(`datetime`) AS `date`
FROM `table`
WHERE ...
) AS `t`
GROUP BY `address`SELECT ANY_VALUE(user_dolg.user_id), ANY_VALUE(users.users_id), users.name,
ANY_VALUE(user_dolg.date), ANY_VALUE(user_dolg.dogovor_name), COUNT(*) AS cnt
FROM users
INNER JOIN user_dolg ON user_dolg.user_id = users.users_id
WHERE `date` BETWEEN '2019-02-01' AND '2019-02-28' AND komandi='командировка'
GROUP BY users.name;