How to split one column to two columns in oracle sql -

please me :

first_name | first_name | middle_name            |            | rrrr eeee  |   rrrr     | eeee            |            |     rrr eeeeeee|   rrr      | eeeeeee              |            |        rr eeeee   |   rr       | eeeee 

i want split first_name first_name , middle_name.

thanks

if have find space character can speed things removing regular expression

select      substr(name, 1, instr(name, ' ')-1) first_name,     substr(name, instr(name, ' ')+1) middle_name  test

or even

select   substr(name, 1, space_pos-1) first_name,   substr(name, space_pos+1) middle_name (select name,              instr(name, ' ') space_pos       test)