replace function in a query

Hi,

I have to write a query that does the following.

select column_x from tbl_xyz
where column_y = 'abc def ghi'

new line characters i.e. '\n' in column_y should be replaced with a space character i.e. ' ' in this query.
Is there any replace function that when used in the query with colulmn_y would do it?

Thanks,
~Harpreet