Last word in a sentence: In SQL (regular expressions possible?)

Question

I need this to be done in Oracle SQL (10gR2). But I guess, I would rather put it plainly, any good, efficient algorithm is fine.

Given a line (or sentence, containing

Answer 1

I reckon it's simpler with INSTR/SUBSTR:

WITH q AS (SELECT 'abc def ghi' AS sentence FROM DUAL)
SELECT SUBSTR(sentence, INSTR(sentence,' ',-1) + 1)
FROM q;