Si "miroir" est un texte inversé, utilisez :
SELECT REVERSE('my_text') FROM dual;
MODIFIER :
SELECT t
,REVERSE(t) AS Mirror1
,TRANSLATE(t, 'abcdefghijklmnopqrstuvwxyz',N'ɐqɔpǝɟbɥıظʞןɯuodbɹsʇnʌʍxʎz') AS Mirror2
,TRANSLATE(REVERSE(t), 'abcdefghijklmnopqrstuvwxyz',N'ɐqɔpǝɟbɥıظʞןɯuodbɹsʇnʌʍxʎz') AS Mirror3
FROM tab;