MySql Daily Report - mysql

Question

I am trying to get some help fixing my complex query. I am explaining below my situation, thanks.
I have the following two tables:
ACTIVITY TABLE:
ID USER_ID CARD_ID CLOCK
1 123 04675545 4/3/2013 1:07:06 PM
2 123 04675545 4/3/2013 2:08:06 PM
3 124 04675550 4/3/2013 2:07:06 PM
4 124 04675550 4/3/2013 4:07:06 PM
5 124 04675550 4/4/2013 10:07:06 AM
6 124 04675550 4/4/2013 2:00:00 PM
7 124 04675550 4/5/2013 4:07:06 PM
8 124 04675550 4/7/2013 8:00:00 AM
9 124 04675550 4/7/2013 5:00:00 PM
PRICE TABLE:
ID FROMTIME TOTIME PRICEPERHOUR
1 08:00:00 19:59:59 50.00
2 20:00:00 07:59:59 75.00
And the following query:
select a.user_id, date(a.clock), ABS(TIME_TO_SEC(TIMEDIFF(a.clock, b.clock))/3600)*c.PRICEPERHOUR as total from
(Select if((#rn:=#rn+1)%2=0,#rn,#rn-1) As rId, act.* from act
join (select #rn:=-1)a
order by user_Id, clock) a
inner join
(Select if((#rn1:=#rn1+1)%2=0,#rn1,#rn1-1) As rId, act.* from act
join
(select #rn1:=-1)b
order by user_Id, clock) b
ON a.rid=b.rid AND a.id <> b.id
inner join
price c
on
TIME_TO_SEC(a.clock) between TIME_TO_SEC(c.FROMTIME)
AND
TIME_TO_SEC(c.TOTIME)
group by a.user_id, date(a.clock)
And I am getting the following result:
USER_ID DATE(A.CLOCK) TOTAL
123 April, 03 2013 00:00:00+0000 50.8333
124 April, 03 2013 00:00:00+0000 100
124 April, 04 2013 00:00:00+0000 194.0833
124 April, 05 2013 00:00:00+0000 1,994.0833
124 April, 07 2013 00:00:00+0000 1,994.0833
However, I am trying to get this result instead:
USER_ID DATE(A.CLOCK) TOTAL
123 April, 03 2013 00:00:00+0000 50.8333
124 April, 03 2013 00:00:00+0000 100
124 April, 04 2013 00:00:00+0000 194.0833
124 April, 05 2013 00:00:00+0000 50
124 April, 07 2013 00:00:00+0000 450
This is part of a clock system. Each time the user check-in, one entry gets recorded on the database. A correct user behavior will be that it has always a pair record recorded. For example user_id 123 clocks at 1:07:06pm and clocks again at 2:08:06pm. However, in some situations, the user may do it just once (unpaired record on the database) and therefore it should only be charged that particular hour from the record. As an example, user 124 on day 4/5/2013.
I am trying all weekend to get this query working :(. Once I get the correct result, I will add a condition to get only one user_id also, (e.g. where user_id=124).

Answer 1

I think even if you manage to do this there are are some potential design pitfalls:
Can people clock in for more than 1 period per day? If so then 2 records for example
10am and 2pm could total 2hours or 4hours.
What happens if people clock in at 11pm and again at 2am?
From a quick glance I don't think your sql takes into account time periods that span across the 2 different pay rates? You should definitely include this scenario in your test data.
If I was going to implement this I would probably move the logic into code, and simplify the price table by only having one time column like:
TIME, PRICE
00:00, 75.00
08:00, 50.00
20:00, 75.00
Also if a user only has one card you may not need to have card_id and user_id in the activity table.