SELECT `id_услуги`, COUNT(`id услуги`)
FROM `услуги`
WHERE `id_отеля` IN (список отелей)
GROUP BY `id_услуги`SELECT `услуги`.`id_услуги`, COUNT(`услуги`.`id услуги`)
FROM `услуги`
RIGHT JOIN `отели` ON `отели`.`id_отеля` = `услуги`.`id_отеля`
WHERE условия выбора отеля
GROUP BY `услуги`.`id_услуги`DELETE `t1`.* FROM `table` AS `t1`
LEFT JOIN (SELECT `id` FROM `table` GROUP BY `field1`, `field2`, ...) AS `t2`
ON `t1`.`id` = `t2`.`id`
WHERE `t2`.`id` IS NULLSELECT `s1`.`id`, `s1`.`city`, `s1`.`contacts`, `s2`.`count`
FROM `spec` AS `s1`
LEFT JOIN (SELECT `contacts`, COUNT(`contacts`) AS `count`
FROM `spec`
GROUP BY `contacts`)
AS `s2` USING (`contacts`)UPDATE `table` SET `sold` = 1 WHERE `sold` = 0 AND `price` <= {$maxprice} AND @id := `id`;
SELECT * FROM `table` WHERE `id` = @id;SET @id := 0;
UPDATE `table` AS `t1`
INNER JOIN (SELECT MIN(`last_use`) AS `last_use` FROM `table`) AS `t2` USING(`last_use`)
SET `t1`.`last_use` = NOW()
WHERE @id = 0 AND @id := `id`;
SELECT *
FROM `table`
WHERE `id` = @id;SELECT *
FROM (SELECT `page_id`, max(`datetime`) AS `datetime`
FROM `f_comments`
WHERE `user` = {$userId}
GROUP BY `page_id`) AS `my`
LEFT JOIN `f_comments` AS `other` ON `other`.`page_id` = `my`.`page_id`
WHERE `other`.`user` != {$userId}
AND `other`.`datetime` > `my`.`datetime`INSERT IGNORE INTO `table` (`field1`, `field2`, `field3`)
VALUES (`valA1`, `valA2`, `valA3`), (`valB1`, `valB2`, `valB3`)INSERT INTO `table` (`field1`, `field2`, `field3`)
VALUES (`valA1`, `valA2`, `valA3`), (`valB1`, `valB2`, `valB3`)
ON DUPLICATE KEY UPDATE `field2` = VALUES(`field2`), `field3` = VALUES(`field3`)DELETE FROM `table` WHERE `field1` IN (`valA1`, `valB1`)