Mysql Insert query with multiple where and join operations - php

Question

Need to insert into the table public_holidays, by the given date that matches holidays table date and it should match CLOCK table clock_in and clock_out time fields and fetch time difference in seconds for 28800 = 8hrs and also need to match designation table from users table user_id, sorry for a very messy code, greatly confused any help could be very helpful thank you.
Clock Table
id user_id date clock_in clock_out created_at updated_at
6 12 2016-06-10 2016-06-10 06:00:00 2016-06-10 14:00:00 2016-06-10 19:20:41 2016-06-10 00:15:51
Users
id first_name last_name designation_id email
1 crysis name 1 crysis#gmail.com
holidays
id date holiday_description created_at updated_at
1 2016-06-10 christmas 2016-06-11 15:23:54 2016-06-11 15:23:54
Designation
designation_id department_id designation created_at updated_at
1 1 employee 2016-01-30 21:03:24 2016-01-30 22:03:24
Department
department_id department_name department_description created_at updated_at
1 IT Info tech 2016-01-30 21:03:24 2016-01-30 21:03:24
Need to insert into this table Public_holidays in the below format by calculating time 8hrs from clock table
user_id department_id designation_id date_cur clock_in clock_out created_at updated_at
12 1 1 2016-06-13 2016-06-10 06:00:00 2016-06-10 14:00:00 2016-06-13 21:03:24 2016-06-13 21:03:24
Tried Messy code
INSERT INTO public_holidays (user_id, department_id,designation_id,clock_in,clock_out) SELECT(cl.user_id,
di.department_id,
di.designation_id,
cl.clock_in,
cl.clock_out)
FROM clock cl, designations di
where
(
select h1.date AS ph_date from holidays h1 WHERE ph_date = 2015-01-22
AND
select (TIMESTAMPDIFF(second,cl.clock_in, cl.clock_out)=28800) AS differ1
AND
INNER JOIN users AS ui ON ui.designation_id = di.id
);

Answer 1

I still don't get the idea, but at least see some relations. Query below will return dataset for all emplyees and all holidays for each of them (h.date column should go into cur_date table). The last JOIN has no relation thus it creates cartesian product - attaches each holiday for each already constructed row (total rows = nuber of empl x number of holidays)
SELECT cl.user_id, di.department_id, di.designation_id, h.date, cl.clock_in, cl.clock_out
FROM clock cl
INNER JOIN users u ON cl.user_id = u.user_id
INNER JOIN designation di ON u.designation_id = u.user_id
CROSS JOIN holidays h --cartesian product: all dates for each row
Don't know what clock table is - standard working hours (one row per employee - I assumed that this is true), daily timesheet (one row per date per employee) or sth else? If its standard working hours then why datetime and not time? If its daily timesheet how should I decide which 8 hrs from that table should you choose (and why 8 hrs)?
Dont know why you calculated/searched for these 8 hrs - do you want to insert holidays for empl. that work 8 hrs only (according to "clock"/in any day)
Don't know what cur_date is (assumed the holiday), but why use date next to datetime - shouldn't be either time or date or datetime only?

Answer 2

Finally this one works #shudder thanks for the help
INSERT INTO public_holidays (user_id, department_id,designation_id,date_cur,clock_in,clock_out)
SELECT cl.user_id, des.department_id , us.designation_id, cl.date,cl.clock_in, cl.clock_out
FROM clock cl
INNER JOIN holidays AS hol ON hol.date = cl.date
INNER JOIN users AS us ON cl.user_id = us.id
INNER JOIN designations AS des ON des.id = us.designation_id
WHERE date(cl.created_at) = '2016-06-13'
AND TIMESTAMPDIFF(second,cl.clock_in, cl.clock_out) = 28800;