How to get next alpha-numeric ID based on existing value from MySQL

Question

First, I apologize if this has been asked before - indeed I\'m sure it has, but I can\'t find it/can\'t work out what to search for to find it.

I need to generate un

Answer 1

A hacky version that works for InnoDB as well.

Replace the insert to companies with two inserts in a transaction:

    INSERT INTO __keys
      VALUES (LEFT(LOWER('Smiths Joinery'),4), LAST_INSERT_ID(1))
    ON DUPLICATE KEY UPDATE
      num = LAST_INSERT_ID(num+1);

    INSERT INTO __companies (comp_name, reference)
    VALUES ('Smiths Joinery',
            CONCAT(LEFT(LOWER(comp_name),4), LPAD(LAST_INSERT_ID(), 4, '0')));

where:

    CREATE TABLE  `__keys` (
      `prefix` char(4) NOT NULL,
      `num` smallint(5) unsigned NOT NULL,
      PRIMARY KEY (`prefix`)
    ) ENGINE=InnoDB COLLATE latin1_general_ci;

    CREATE TABLE  `__companies` (
      `comp_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
      `comp_name` varchar(45) NOT NULL,
      `reference` char(8) NOT NULL,
      PRIMARY KEY (`comp_id`)
    ) ENGINE=InnoDB COLLATE latin1_general_ci;

Notice:

• latin1_general_ci can be replaced with utf8_general_ci,
• LEFT(LOWER('Smiths Joinery'),4) would better become a function in PHP