ISO weeknumbers

From: Terry Dykstra <>
Date: Mon, 05 Jan 2009 20:41:16 GMT
Message-ID: <Mfu8l.1618$Db2.1293_at_edtnps83>

The IW format string returns the ISO week number


     Week of year (1-52 or 1-53) based on the ISO standard.

I'm confused by this. When would you get week 53? For example, when running this against the last week of 2008 (using SE) , it switches from week 52 to week 1 while still in December.

select to_char(to_date('20081228','yyyymmdd') ,'IW') from dual;
> 52

select to_char(to_date('20081229','yyyymmdd') ,'IW') from dual;
> 01

Terry Dykstra 
Received on Mon Jan 05 2009 - 14:41:16 CST

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