How to Extract Week Numbers from Dates in SQL Without Null Values?

Extracting Week Numbers in SQL

You're attempting to extract the week number from a date column that has been converted from VARCHAR2 to DATE format. However, you're encountering null values.

To resolve this issue, you need to reconvert the date back to VARCHAR2 using the desired mask:

to_char(to_date('01/02/2012', 'MM/DD/YYYY'), 'WW')

This will extract the week number in a VARCHAR2 format.

If you prefer a numeric week number, you can wrap the statement in TO_NUMBER():

to_number(to_char(to_date('01/02/2012', 'MM/DD/YYYY'), 'WW'))

Additionally, you have multiple week number options to choose from:

• WW: Week of year, starting from the first day of the year
• W: Week of month, starting from the first day of the month
• IW: Week of year, based on the ISO standard

Consider your specific requirements when selecting the appropriate parameter for your extraction.

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