title: Python/sqlite: get column values as a list/tuple from rows where other columns have certain values
body: <p>I have a sqlite table with 4 columns, say: id, pagenr, x1, y1.
  I need to get the y1 column values as a list/tuple, but only from rows where pagenr and x1 have certain values. Help much appriciated. NB: I am using python 2.6.</p>