> > I have a table doing time tracking. I don't use timestamps, I use
> > datetime fields to record punch in times and punch out times. I
> > have this query that computes the amount of time between a punch in
> > and punch out:
> > select SEC_to_time(unix_timestamp(TTendTime) -
> > as endtime
> > FROM TimeTracking
> > WHERE TTperson = 1
> > and date(TTstartTime) = '2005-10-19'
> > And this works great except for when people punch in and out several
> > times in one day. Is there any way I can total a number of records
> > into one total time? In this example case, I am TTperson #1 and I
> > punched in and out five times this day.
> > I know I can do it in the code, but if I can do it in sql, life
> > would be better for me.
> > --ja
> > --
> Let's do some basic algebra:
> et = end time
> st = start time
> Total time = (et1 - st1) + (et2 - st2) + ... + (etN - stN)
> Where N = how many clock-ins and clock outs they had.
> We can rewrite this as
> TT = et1 - st1 + et2 - st2 + ... etN - stN
> = et1 + et2 + ... etN - st1 - st2 - ... - stN
> = et1 + et2 + ... etN - (st1 + st2 + ... + stN)
> = SUM(et(1..N))-SUM(st(1..n))
> This translated to SQL as:
> select SEC_to_time(SUM(unix_timestamp(TTendTime)) -
> as endtime
> FROM TimeTracking
> WHERE TTperson = 1
> and date(TTstartTime) = '2005-10-19'
Won't this fail if it overflows 24 hours?
Given that the result of SEC_TO_TIME seems to be a valid "time value",
which "duration" is not?
eg: a duration can be 25 hours long, while a TIME value cannot.
Database Workbench - tool for InterBase, Firebird, MySQL, Oracle & MS SQL
Database development questions? Check the forum!