Process integer fields

[sc5502]

I have an integer field that contains values from 1 to whatever. When it contains a 0 value, it means an unknown value. Can I display this in SQL

Number
-------
1
24
Unknown
876

instead of this

Number
-------
1
24
0
876


If it can be done how do I go about it? Thanks in advance.

[Luuk]

SELECT 
  CASE WHEN Number=0 THEN 'Unknown' ELSE str(Number) END AS Number
FROM Table;