MySQL INSERT …ON DUPLICATE UPDATE - Adds one to the autoincrement

Question

I keep track of all the http_user_agents that visit me, with a simple hit counter. The below insert the http_user_agent in the DB, this field is Case Insensitive and is Uniq

Answer 1

You can first calculate the maximum number of inserted rows and add 1 to it,

(SELECT MAX(`id`)+1 FROM `tblRefHttpUsersAgent`)

then alter the table AUTO_INCREMENT using some variables SET @NEW_ID and PREPARE / EXECUTE statements.

here is a simple solution for the same problem and below is the finished version if you like the solution of your own specific problem:

    $sql = 'SET @NEW_AI = (SELECT MAX(`id`)+1 FROM `tblRefHttpUsersAgent`);
                    SET @ALTER_SQL = CONCAT("ALTER TABLE `tblRefHttpUsersAgent` AUTO_INCREMENT =", @NEW_AI);
                    PREPARE NEWSQL FROM @ALTER_SQL;
                    EXECUTE NEWSQL;';

    $sql .= 'INSERT INTO `db_agency_cloud`.`tblRefHttpUsersAgent` SET `http_users_agent` = :UsersAgent, `created_ts` = NOW() ON DUPLICATE KEY UPDATE `hits` = `hits` + 1';