explain analyze

Hello, ia have an SQl query of the following form :

select Y.at from table Y where Y.at >=1 and Y.at < 253214

I have state an index on attribute at and by using the explain in front of
the select ... i get the information of an index scan-however i can't
distingusish whether that index scan refers to one of the two comparisons
or to the conjuction of those two - how i can see that?
explain analyze works on that question?


                                                 SWTHRHS TOYRTOYNHS
                                                (tourtoun@csd.uch.gr)