This operator is only available when connected to an Aster database.
The Extract Quarter operator returns the week of the year that the date/time stamp argument falls within.
The week count starts from the first full week of the year, so early dates in January will be part of the previous year’s final week.
When dragging an Extract Week operator into a variable, the following tree element is created.Variable Creation > Input > Variables: SQL Elements pane - Date and Time > Extract Week

This concludes discussion of the Extract functions.