Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource

<?
    require_once($DATA_ACCESS_PATH."db_connect.inc.php");
        
    function getAllJournalsByPatientId($patientId)
    {
        global $JOURNALS_TABLE;
        $query = "SELECT ID,BEGIN_DATE,END_DATE,TEXT FROM $JOURNALS_TABLE WHERE PATIENT_ID=$patientId ORDER BY BEGIN_DATE";
        $result = mysql_query($query);
        $journals = array();
        while ($row = mysql_fetch_array($result)) {
            $journals[] = $row;
        }
        return $journals;
    }
    
    function getJournalById($journalId)
    {
        global $JOURNALS_TABLE;
        $query = "SELECT ID,BEGIN_DATE,END_DATE,TEXT FROM $JOURNALS_TABLE WHERE ID=$journalId";
        $result = mysql_query($query);
        return mysql_fetch_array($result);
    }
    
    function createJournal($id, $beginDate, $endDate, $text, $patientId)
    {
        global $JOURNALS_TABLE;
        if (!empty($id)) {
            $query = "UPDATE $JOURNALS_TABLE SET BEGIN_DATE='$beginDate',END_DATE='$endDate',TEXT='$text' WHERE ID=$id";
            mysql_query($query);
        } else {
            $query = "INSERT INTO $JOURNALS_TABLE(BEGIN_DATE,END_DATE,TEXT,PATIENT_ID) ";
            $query .= "VALUES('$beginDate','$endDate','$text',$patientId)";
            mysql_query($query);
        }
    }
    
    function deleteJournal($id)
    {
        global $JOURNALS_TABLE;
        if (!empty($id)) {
            $query = "DELETE FROM $JOURNALS_TABLE WHERE ID=$id";
            mysql_query($query);
        }
    }
?>