Perfect !!!!! Thank you very much for your help!!!! Here is the final solution in case other people have the same problem: CAST (YEAR(current_date) as char(4)) || case when WEEK_OF_YEAR(current_date) < 10 THEN '-0' ELSE '-' END || CAST (WEEK_OF_YEAR(current_date) as char(2))

Thank you very much for your answer !! And it works !! Now I have another problem, some dates appear: 2017-1 instead of 2017-01 how to get around the problem? I would like to present these dates in a diagram in chronological order and without the '0' it distorts everything. Thank you again for your answer !