SQL weeknumber issue: wrong weeknumber Hi, I am trying to extract the weeknumber from a date. But both my SQL statements return the wrong weeknumber. Here is my first statement: SELECT to_char(to_date(cf$_co_date_order, 'dd-mm-yyyy'), 'ww') FROM customer_order_cfv Statement returns: 22-3-2021 0:00 12 23-3-2021 0:00 12 24-3-2021 0:00 12 24-3-2021 0:00 12 25-3-2021 0:00 12 26-3-2021 0:00 13 26-3-2021 0:00 13 26-3-2021 0:00 13 26-3-2021 0:00 13 My second statement: SELECT to_char(to_date(cf$_co_date_order, 'dd-mm-yyyy'), 'iw') FROM customer_order_cfv Statement returns: 22-3-2021 0:00 12 23-3-2021 0:00 12 24-3-2021 0:00 13 24-3-2021 0:00 13 25-3-2021 0:00 13 26-3-2021 0:00 13 26-3-2021 0:00 13 26-3-2021 0:00 13 26-3-2021 0:00 13 So both are wrong. I expect every date to return weeknumber 12, because that is the correct weeknumber. Does someone know how to achieve this?