update table_name set (col1,col2,col3)=(select t.col4,t.col5,t.col6 from table_name2 t where something)
OR
create table tgt ( id number /*primary key*/, x number, y number )/insert into tgt ( id, x, y )select level, level, level from dual connect by level < 4/create table src ( id number /*primary key*/, x number, y number )/insert into src ( id, x, y )select level+1, level*5, level*5 from dual connect by level <...