Nested SELECT statements problem

[Pascal Délisle]

Hi!

I try to figure out how to use a nested "SELECT" statement after the 
"IN" predicate.  For example, when I try this code, it doesn't return 
anything although it should:


SELECT book.IDLivre, aut.Prenom, aut.Nom FROM livre book, livreEcritPar 
ecr, auteur aut WHERE ecr.IDLivre = book.IDLivre AND aut.IDAuteur = 
ecr.IDAuteur AND book.IDLivre IN ("SELECT book.IDLivre FROM livre book, 
livreEcritPar ecr, auteur aut WHERE aut.Prenom like '%$firstName%' AND 
aut.Nom like '%$name%' AND ecr.IDAuteur = aut.IDAuteur AND book.IDLivre 
= ecr.IDLivre");


So, my question is the following:  How should I change syntax in order 
to make this bunch of code work?  I mean, under Oracle SQL, this syntax 
would be legal and work perfectly, so I'm confused how to solve my 
problem.

Thanks in advance!