How can I apply columns to a table only?

I have a very long table that I want to put into two columns to save space. But when I select the table with CTRL-A-A and go to every column menu listed in the relevant help topic, the only available option is to apply the columns to the whole page, which I don’t want to do. Inserting a frame onto the table simply made it disappear, and I couldn’t undo the action for some reason.

Are you working in Calc or in Writer?

Just select the table with one paragraph above. Then choose Insert - Section - Columns
Insert Section

I used Format - Columns but it still works. Thank you!