public function where($where, $parse = null) {
// 添加如下代码可以实现
$where_str = '';
if ( is_array($where) ) {
foreach ( $where as $k => $v ) {
$where_str .= is_int($k)? $v.' AND ' : '`' . $k . "`='" . $v . "' AND ";
}
$where = substr($where_str, 0, -5);
}
// 这里结束
if ( !is_null($parse) && is_string($where) ) { 