急问一个小疑点，php中mysql语句

急，问一个小问题，php中mysql语句
set @count = 0;
select index from (select (@count := @count+1) as index ,id from table ) as abc ;
这句话怎么改成php可以执行的，那个变量怎么声明赋值，求大大解惑！

------解决方案--------------------

PHP code

//分两次执行。
mysql_query('set @count = 0');
$result = mysql_query('select index from (select (@count := @count+1) as index ,id from table ) as abc');