this has nothing to do with SQL Workbench/J.
Whether or not `date_part()` with a ISO week is supported or not, totally depends on the database product being used.
SQL Workbench only sends your query to the database server - there is nothing SQL Workbench/J can do about, if your database doesn't support the features you need.
If you are using Postgres (which the use of date_part() seems to suggest), then date_part('week') will return the ISO week.
Typically this only makes sense if you combine it with the ISO year.