I want to select all links where the lowest invert level of the links that leave the node is greather than the lowest invert level of the links that come in a node.

I’ve tried with the queries
· us_links.ds_invert >ds_links.us_invert
· us_links.invert >ds_links.invert
· min(us_links.ds_invert) >min(ds_links.us_invert)


None of the queries work. What did I do wrong ?