oracle - Assign a Select to a variable in a stored procedure

Question

I try to create a procedure in my Oracle Database and can't achieve to assign the result of a query to my variables. Here is what i'm trying to debug :

create or replace
PROCEDURE PCD_COMBAT (identifier_perso NUMBER, identifier_advers NUMBER) AS

ATT_PERSO NUMBER;
OFF_PERSO NUMBER;
DEF_ADVERS NUMBER;

BEGIN

OFF_PERSO := SELECT OFFENSE_PERSO FROM PERSONNAGE WHERE ID_PERSO = identifier_perso;
DEF_ADVERS := SELECT DEFENSE_ADVERSAIRE FROM PERSONNAGE WHERE ID_ADVERSAIRE = identifier_advers;
ATT_PERSO := OFF_PERSO - DEF_ADVERS;
IF ATT_PERSO < 1 { ATT_PERSO := 1 };

END PCD_COMBAT;

It clearly says in Oracle Developper that my Select doesnt please him and can't figure out why. Oracle library, forums and code samples I read didnt help much.