Map integer(id) to text string?

The only way (I’m fairly sure) to do this is using a CASE .. WHEN ... construct:

SELECT *, CASE type WHEN 1 THEN 'abc' WHEN 2 THEN 'xyz' END as stringType
FROM orders

You can also use the ELSE clause to specify a default, e.g. CASE type WHEN 1 THEN 'abc' WHEN 2 THEN 'xyz' ELSE 'unknown' END.