Excel WEEKNUM() vs MySQL YEARWEEK() - mysql

Question

I am creating a clock-in time system and so far I have been able to get user clock in time for today and user clock in time for the current week.
The final step is to get user current time for the current pay period.
I have created a list of pay period start & end dates in Excel.
Whenever you use a function like Excel WEEKNUM() or MySQL YEARWEEK(), these functions come with an additional option parameter.
The links below show the differences between these modes in a table.
Excel WEEKNUM() table reference
MySQL YEARWEEK() table reference
My question is, if we do payroll biweekly, which mode do I set in Excel WEEKNUM() that corresponds to MySQL YEARWEEK()?
Attached spreadsheet clock.logic.xlsx
Thank you for any help.

Answer 1

At first the good news: The Excel ISOWEEKNUM function corresponds to the MySQL WEEKOFYEAR which is WEEK(date,3). So determining ISO week numbers is possible.
But all other WEEK modes are simply crap because the definition of the first week in year does not fit any logic used elsewhere. For example, take the simplest mode having Sunday as the first day of the week and the first week of the year is the week, the first day of the year falls in. This is what Excels WEEKNUM function returns with Return_type 1 or omitted. This should be MySQLs WEEK in modus 0 (0-53) or 2 (1-53). But what the heck?
SELECT WEEK('2008-01-01',0); -> 0
SELECT WEEK('2008-01-01',2); -> 52
So MySQL tells us, Tuesday, 2008-01-01, is in week 52 of 2007?
Really? Why?
Because the rule "Week 1 is the first week … with a Sunday in this year" is not fulfilled by MySQL. Instead it seems for MySQL the first week starts with the first Sunday in this year.
So except of the ISO week numbers, all other week numbers from MySQL are wrong. One could think: Let us take modus 0 and simply add 1 to the result. But that fails in 2012. Because there 2012-01-01 is Sunday and there MySQL gives week number 1 in modus 0 as well as in modus 2.
Examples:
Excel:
Date WEEKNUM ISOWEEKNUM
2008-01-01 1 1
2008-02-01 5 5
2008-02-03 6 5
2008-02-04 6 6
2008-12-31 53 1
2009-01-01 1 1
2009-02-01 6 5
2009-12-31 53 53
2012-01-01 1 52
2012-02-01 5 5
2012-12-31 53 1
2016-01-01 1 53
2016-02-01 6 5
2016-12-31 53 52
MySQL:
drop table if exists tmp;
create table tmp (d date);
insert into tmp (d) values
('2008-01-01'),
('2008-02-01'),
('2008-02-03'),
('2008-02-04'),
('2008-12-31'),
('2009-01-01'),
('2009-02-01'),
('2009-12-31'),
('2012-01-01'),
('2012-02-01'),
('2012-12-31'),
('2016-01-01'),
('2016-02-01'),
('2016-12-31');
select d as 'Date', week(d,0), week(d,3) from tmp;
Result:
Date week(d,0) week(d,3)
2008-01-01 0 1
2008-02-01 4 5
2008-02-03 5 5
2008-02-04 5 6
2008-12-31 52 1
2009-01-01 0 1
2009-02-01 5 5
2009-12-31 52 53
2012-01-01 1 52
2012-02-01 5 5
2012-12-31 53 1
2016-01-01 0 53
2016-02-01 5 5
2016-12-31 52 52

Answer 2

If you want to calculate hours in current pay period in Excel, given a two week pay period, then I'd suggest that you don't need week numbers at all (in fact that overcomplicates the calculation, especially at the start or end of the year)
If you have dates in A2:A100 and hours worked on those dates in B2:B100, and a list of pay period start dates in Z2:Z10 then you can get hours in current pay period with this formula
=SUMIF(A2:A100,">="&LOOKUP(TODAY(),Z2:Z10),B2:B100)
I imagine your actual setup is more complicated, but some variation on the above can probably still be used