//计时开始

runtime();

//执行查询

mysql_query($sql);

//计时结束.

echo runtime(1);

//计时函数

function   runtime($mode=0)   {

    static   $t;

    if(!$mode)   {

        $t   =   microtime();

        return;

    }

    $t1   =   microtime();

    list($m0,$s0)   =   explode("   ",$t);

    list($m1,$s1)   =   explode("   ",$t1);

    return   sprintf("%.3f ms",($s1+$m1-$s0-$m0)*1000);

} 

$t1=microtime(true);

mysql_query($sql);

echo microtime(true)-$t1;