Finding free blocks of time in mysql and php?

Question

I have a table in mysql like this:

+------------+------------+------------+------------+ 
|     date   |   user_id  | start_hour | end_hour   | 
+-----------         


        

Answer 1

Try this Query i hope its work for you.....

SELECT
  a.id,
  a.end_hour    AS `Free time Start`,
  la.start_hour AS `Free Time End`,
  IFNULL(TIMEDIFF(la.start_hour, a.end_hour),'00:00:00') AS `Total Free Time`
FROM appointment AS a
  LEFT JOIN (SELECT *
             FROM appointment
             LIMIT 1,18446744073709551615) AS la
    ON la.id = (SELECT
                  id
                FROM appointment
                WHERE id NOT IN(a.id)
                ORDER BY (a.id > id)ASC
                LIMIT 1);