Hello,
we also have the need to duplicate columns, but with the content, not just the title and field type. From one table to the same table, but also to another table, in the same database or not. And of course, to select a whole column, if the number of row is large, we should not do it by dragging the mouse from the first to the last line of the column, we need a way to select the whole column in one click, as in Calc or Excel (see Implement paste (the other friend of copy/paste) and the ability to select an entire line in one click - #6 by Vincent for a discussion on the multiple selection of row with click CTRL+click and SHIFT+click)