The ISOWEEKNUM() function returns number of the week which the date falls into. Note that this function is compliant with the ISO8601 standard: a week always begins on a Monday, and ends on a Sunday. The first week of a year is that week which contains the first Thursday of the year.
De funksje ISOWIKENÛM () jout it wikenûmer werom wêryn' t de opjûne datum falt. Opmerking: dizze funksje folget de ISO8601- standert: in wike begjint altyd op in moandei, en einiget op in snein. De earste wike fan in jier is de wike wêryn' t de earste tongersdei fan dat jier falt.