OK...
Thank you!

CONTROLLER:

global class AAAACSV implements System.Schedulable {
public String mailSouhaite {get; set;}
public string caseTT {get; set;}
 
global void execute(SchedulableContext sc) {
planifier();
}

public void planifier(){
String query = caseTT;
String premier=query.substringAfter('select');    
premier=  premier.substringBefore('from');
   
string titre= premier+'\n';
string contenuCSV = titre;

String aaa = 'Case';
  
for(aaa a: (List<aaa>)database.query(caseTT))
{
   string contenu = a.casenumber + ',' + a.subject+ ',' +a.Contact.Name+ ',' + a.status +'\n';
   contenuCSV = contenuCSV + contenu ;
}

Messaging.EmailFileAttachment csvPJ = new Messaging.EmailFileAttachment();
blob csvBlob = Blob.valueOf(contenuCSV);
nomFichierCSV = 'cases_fermes_'+Date.today().format()+'.csv';
csvPJ.setFileName(nomFichierCSV);
csvPJ.setBody(csvBlob);
Messaging.SingleEmailMessage email =new Messaging.SingleEmailMessage();
String[] adressMail = new list<string> {mailSouhaite};
String subject = 'Rapport Cases Fermés CSV - '+Date.today().format();
email.setSubject(subject);
email.setToAddresses(adressMail);

email.setPlainTextBody('mail...............');
                       
email.setFileAttachments(new Messaging.EmailFileAttachment[]{csvPJ});
Messaging.SendEmailResult [] envoyer = Messaging.sendEmail(new Messaging.SingleEmailMessage[] {email});

}
}

PAGE:
<apex:page controller="AAAACSV">
    <style type="text/css">
        .classeRequete { width: 600px; }
        .classeMail { width: 400px; }
    </style>
      
  <apex:form >
  <apex:PageBlock >
    :::::::::: PARAMETRAGE :::::::::: <br /><br />
    Mail..........:&nbsp;<apex:inputText styleClass="classeMail" value="{!mailSouhaite}"/><br /><br />
    Requête :&nbsp;&nbsp;<apex:inputText styleClass="classeRequete" value="{!caseTT}"/><br /><br />
    <apex:commandButton value="Valider" action="{!planifier}"/> <br/><br/>
    <apex:commandButton value="Effacer"/> <br/><br/>
  </apex:PageBlock>
  </apex:form>
</apex:page>