order after WHERE clause

Is it possible that I get different query result time if I change two
parts of the WHERE clause? I.e.,

SELECT * FROM table WHERE col1 = 5 AND col2 = 6;

and

SELECT * FROM table WHERE col2 = 6 AND col1 = 5;

In general, is it important how I define the ordering in a WHERE clause?

TIA, Zoltan

--                         Kov\'acs, Zolt\'an                        kovacsz@pc10.radnoti-szeged.sulinet.hu
          http://www.math.u-szeged.hu/~kovzol                        ftp://pc10.radnoti-szeged.sulinet.hu/home/kovacsz