function mysql_where($criteriaArray = null, $extraWhere = 'TRUE')
{
    $where = '';
    if ($criteriaArray) {
        foreach ($criteriaArray as $fieldName => $value) {
            if (!preg_match('/^(\\w+)$/', $fieldName)) {
                die(__FUNCTION__ . ": Invalid column name '" . htmlencode($fieldName) . "'!");
            }
            // error checking: whitelist column chars to prevent sql injection
            // if $value is an array, use the IN operator
            if (is_array($value)) {
                $where .= "`{$fieldName}` IN (" . mysql_escapeCSV($value) . ") AND ";
            } else {
                $where .= mysql_escapef("`{$fieldName}` = ? AND ", $value);
            }
        }
    }
    $where .= $extraWhere;
    return $where;
}
function mysql_getValuesAsCSV($valuesArray, $defaultValue = '0')
{
    return mysql_escapeCSV($valuesArray, $defaultValue);
}