Where in Editor with a variable

I want a complex Where with a variable. In its basic version it's something like this :

->where( function ( $q ) {
            $q->where( "wp_qspread_invite.parrain", $_SESSION['user_id'], '<>' );
            $q->where( 'wp_qspread_invite.invitation', "(SELECT ID FROM wp_qspread_invitation WHERE id_createur = 1)", 'IN', false );
    } )

But in place of WHERE id_createur = 1

I want

WHERE id_createur = $_SESSION['user_id']

I tried different syntaxes without success. What is the correct way to do it? Thx