calc on the fly doesn't work

for testing I've copied the little example you show in "How to Use Calculated Fields" but it just won't work.

I've entered this in Edit SQL query:
select `price`,

`quantity`

price * quantity as value

From `test_calc`
I get this:

Cannot retrieve columns information. Please modify SQL query and try again.
I can't find my mistake!!! <img src='https://asprunner.com/forums/file.php?topicimage=1&fieldname=question&id=3259&image=1&table=forumtopics' class='bbc_emoticon' alt=':(' />