NOT IN я так понял https://w3resource.com/mysql/comparision-functions... работает начиная с 5.6
echo 1 <=> 1; //ouputs 0
echo 3 <=> 4; //outputs -1
echo 4 <=> 3; //outputs 1echo "x" <=> "x"; // ouputs 0
echo "x" <=> "y"; //ouputs -1
echo "y" <=> "x"; //ouputs 1
$users[] = 1; // ID пользователя
$q = "SELECT * FROM table regexp '[[:<:]](" . implode( '|', $users) . ")[[:>:]]";users
id, first_name, last_name, ...
chats
id, user_id, name, ...
chats_users
chat_id, user_id$q = "SELECT * FROM table WHERE FIND_IN_SET('1', `users`)"; // 1 - ID пользователя
SELECT *
FROM (
SELECT *
FROM `table`
ORDER BY `date` DESC
LIMIT 8
) AS `a`
ORDER BY `date` DESC, `price`
SELECT partnum,
LAG(partnum) OVER w AS 'prev_partnum',
partnum - LAG(partnum) OVER w AS 'diff'
FROM nspcl
WINDOW w AS (ORDER BY id);