updating mysql table

hi, anybody knows how to do the following: i've got two tables with the same field structure. i want table x update according to table y. what's the correct php mysql statement? i tried: mysql_query("update x set (fld1, fld2, ..) = (select fld1, fld2, .. from y where fld3='xyz') where fld3='xyz'", $connection); mysql_query("update x set (select * from y where fld3='xyz') where fld3='xyz'", $connection); mysql_query("update x set (*) = (select * from y where fld3='xyz') where fld3='xyz'", $connection); according to my sql reference syntax guide, the first attempt should have worked. (the .. stands for all the rest fields in the table) regards libor matyas