>>SELECT ciglid from mutuelle WHERE ciglid in (SELECT ciglid FROM mutuelle mut WHERE ciglid = '0000000015') INTO CURSOR temp
That will return the same as Tore's example: the rows where ciglid= '0000000015' will be returned.
I think the problem is that your inner SELECT uses the same table and field names when perhaps they should be different?
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1