Searching on Concat string not working to find against multiple fields

Question

I have this query that I use for searching customer's last names which is working fine:

SELECT `pt_bookings`.`booking_id`,
    `pt_bookings`.`booking_date`,
    pt_bookings.booking_ref_no,
    `ai_last_name`,
    `pt_bookings`.`booking_checkout`,
    `pt_bookings`.`booking_checkin`
FROM (`pt_bookings`)
    INNER join pt_accounts on pt_accounts.accounts_id = pt_bookings.accounts_id
      AND pt_accounts.accounts_type='customers'
WHERE ai_last_name LIKE CONCAT('%jansen%')

But I would like to search on a string of 3 concatenated varchars ai_firstname ai_middle_name ai_last_name and I would prefer to use this query but it returns 0 records and does not throw any error. What is wrong about this query? Thanks!

SELECT `pt_bookings`.`booking_id`,
    `pt_bookings`.`booking_date`,
    pt_bookings.booking_ref_no,
    CONCAT(`pt_accounts`.`ai_first_name`,
        `pt_accounts`.`ai_middle_name`,
        `pt_accounts`.`ai_last_name`) as customer_name,   
    `pt_bookings`.`booking_checkout`,
    `pt_bookings`.`booking_checkin`
FROM (`pt_bookings`)
    INNER join pt_accounts on pt_accounts.accounts_id = pt_bookings.accounts_id
      AND pt_accounts.accounts_type='customers'
WHERE customer_name LIKE CONCAT('%jansen%')

Answer 1

This is your query:

SELECT b.`booking_id`, b.`booking_date`,  b.booking_ref_no, 
       CONCAT(`a.`ai_first_name`, a.`ai_middle_name`, a.`ai_last_name`) as customer_name,
      b.`booking_checkout`, b.`booking_checkin`
FROM pt_bookings b INNER join
     pt_accounts a
     on a.accounts_id = b.accounts_id AND
        a.accounts_type = 'customers'
WHERE customer_name LIKE  CONCAT('%jansen%');

The main problem is that customer_name is a column alias, so you cannot use it in a WHERE. MySQL has a convenient extension, that allows this logic in a HAVING clause:

HAVING customer_name LIKE '%jansen%'

I'm not sure what the CONCAT() is for. There is no reason to use it with one argument.