where is weight stored?

" It uses the node table's 'sticky' column to store weights as well as sticky information (so that feature is not lost)."

I changed the weights on a couple of nodes (via Content). Values offered where in the range 0 to -20 (minus 20).
But looking at the DB, sticky for these nodes is still 0. If I edit the individual node I can see the correct new weight, e.g. -8. etc. in the Weight tab.
In my Views the same story. I changed it to sort on sticky and then date. But the sticky had no effect. Then I saw the Weight option and added that instead. Now the page works as desired.
So my View is OK.

My question is: how to handle the weight in my own views_query_alter.
I had some sql code ready sorting on node.sticky - but it has no effect, sticky is always 0.
Do I have to JOIN on something? Can't see a weight table in the DB, or a weight column in node.

Very mysterious!
Help appreciated