WEEK(NOW()) en date('W')

En wat zegt de PHP-handleiding?

MySQL

#

WEEK(date[,mode])

This function returns the week number for date. The two-argument form of WEEK() allows you to specify whether the week starts on Sunday or Monday and whether the return value should be in the range from 0 to 53 or from 1 to 53. If the mode argument is omitted, the value of the default_week_format system variable is used. See Section 5.1.3, “System Variables”.

The following table describes how the mode argument works.
First day
Mode of week Range Week 1 is the first week …
0 Sunday 0-53 with a Sunday in this year
1 Monday 0-53 with more than 3 days this year
2 Sunday 1-53 with a Sunday in this year
3 Monday 1-53 with more than 3 days this year
4 Sunday 0-53 with more than 3 days this year
5 Monday 0-53 with a Monday in this year
6 Sunday 1-53 with more than 3 days this year
7 Monday 1-53 with a Monday in this year

mysql> SELECT WEEK('1998-02-20');
-> 7
mysql> SELECT WEEK('1998-02-20',0);
-> 7
mysql> SELECT WEEK('1998-02-20',1);
-> 8
mysql> SELECT WEEK('1998-12-31',1);
-> 53

Note that if a date falls in the last week of the previous year, MySQL returns 0 if you do not use 2, 3, 6, or 7 as the optional mode argument:

mysql> SELECT YEAR('2000-01-01'), WEEK('2000-01-01',0);
-> 2000, 0

One might argue that MySQL should return 52 for the WEEK() function, because the given date actually occurs in the 52nd week of 1999. We decided to return 0 instead because we want the function to return “the week number in the given year.” This makes use of the WEEK() function reliable when combined with other functions that extract a date part from a date.

If you would prefer the result to be evaluated with respect to the year that contains the first day of the week for the given date, use 0, 2, 5, or 7 as the optional mode argument.

mysql> SELECT WEEK('2000-01-01',2);
-> 52

Alternatively, use the YEARWEEK() function:

mysql> SELECT YEARWEEK('2000-01-01');
-> 199952
mysql> SELECT MID(YEARWEEK('2000-01-01'),5,2);
-> '52'

bedankt voor jullie hulp :)
dit was ook voldoende geweest hoor:
the ISO week number corresponds to WEEK(date, 3)

Vreemd genoeg krijg ik als ik [code language="php"] $sql="SELECT week(current_DATE), 1"; [/code] invoer in een PHP document geen resultaat. Weet iemand hoe ik dit oplos?

je selecteert deze week, en het getal 1. maar waar selecteer je het uit, en waarschijlijk bedoel je een WHERE statement

erwin schreef op 28.04.2008 18:28

je selecteert deze week, en het getal 1. maar waar selecteer je het uit, en waarschijlijk bedoel je een WHERE statement

Ik dacht hetzelfde te doen als wat in het voorbeeld beschreven werd.
# [
mysql> SELECT WEEK('2000-01-01',2);
-> 52
]

Maar dan door de datum in te stellen op de 'huidige datum'.
Wel door eerste verbinding te maken met de database, maar zonder een tabel te selecteren.