Select Case no Mysql

Simples:

SELECT id, nome, descricao,
CASE status
     WHEN 1 THEN 'Aprovado'
     WHEN 2 THEN 'Vencido'
     WHEN 3 THEN 'Pendente'
     WHEN 0 THEN 'Reprovado'
END AS status

FROM tabela

Fonte:http://talibamartins.wordpress.com/2007/09/20/if-e-case-no-mysql/