Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in ...可以正确的得到结果，但是有warning!是什么

Question

这个提示就是result不对啊。。

Answer 1

<?php
class MySQL {    var $obj = array ( "sql_database"   => ""         ,
                       "sql_user"       => "root"     ,
                       "sql_pass"       => ""         ,
                       "sql_host"       => "localhost",
                       "sql_port"       => ""         ,
                       "persistent"     => "1"         ,
                       "cached_queries" => array(),
                       'debug'          => 0,
                     );
 var $database      = "";                     
     var $query_id      = "";
     var $connection_id = "";
     var $query_count   = 0;
     var $record_row    = array();
     var $return_die    = 0;
     var $error         = "";
    
             
    /*========================================================================*/
    // Construtor
    /*========================================================================*/  
                   
    function MySQL($host, $db, $user, $password, $persistent, $hideError=1) {

$this->obj = array ( "sql_database"   => $db         ,
                       "sql_user"       => $user     ,
                       "sql_pass"       => $password         ,
                       "sql_host"       => $host,
                       "sql_port"       => ""         ,
                       "persistent"     => $persistent         ,
                       "cached_queries" => array(),
                       'debug'          => 0,
                     );
$this->database = $db;
$this->return_die = $hideError;
               
    }
function query($the_query, $bypass=0) {
    
        $this->query_id = mysql_query($the_query, $this->connection_id);
      
        if (! $this->query_id )
        {
            $this->fatal_error("mySQL query error: $the_query");
        }
        
        if ($this->obj['debug'])
        {
         $endtime = $Debug->endTimer();
        
         if ( preg_match( "/^select/i", $the_query ) )
         {
         $eid = mysql_query("EXPLAIN $the_query", $this->connection_id);
         echo "<table width='95%' border='1' cellpadding='6' cellspacing='0' bgcolor='#FFE8F3' align='center'>
   <tr>
     <td colspan='8' style='font-size:14px' bgcolor='#FFC5Cb'><b>Select Query</b></td>
   </tr>
   <tr>
    <td colspan='8' style='font-family:courier new, courier, monaco, arial;font-size:14px'>$the_query</td>
   </tr>
   <tr bgcolor='#FFC5Cb'>
 <td><b>table</b></td><td><b>type</b></td><td><b>possible_keys</b></td>
 <td><b>key</b></td><td><b>key_len</b></td><td><b>ref</b></td>
 <td><b>rows</b></td><td><b>Extra</b></td>
   </tr>\n";
while( $array = mysql_fetch_array($eid) )
{
$type_col = '#FFFFFF';

if ($array['type'] == 'ref' or $array['type'] == 'eq_ref' or $array['type'] == 'const')
{
$type_col = '#D8FFD4';
}
else if ($array['type'] == 'ALL')
{
$type_col = '#FFEEBA';
}

echo "<tr bgcolor='#FFFFFF'>
 <td>$array[table]&nbsp;</td>
 <td bgcolor='$type_col'>$array[type]&nbsp;</td>
 <td>$array[possible_keys]&nbsp;</td>
 <td>$array[key]&nbsp;</td>
 <td>$array[key_len]&nbsp;</td>
 <td>$array[ref]&nbsp;</td>
 <td>$array[rows]&nbsp;</td>
 <td>$array[Extra]&nbsp;</td>
   </tr>\n";
}

if ($endtime > 0.1)
{
$endtime = "<span style='color:red'><b>$endtime</b></span>";
}

echo "<tr>
  <td colspan='8' bgcolor='#FFD6DC' style='font-size:14px'><b>mySQL time</b>: $endtime</b></td>
  </tr>
  </table>\n<br />\n";
}
else
{
  echo "<table width='95%' border='1' cellpadding='6' cellspacing='0' bgcolor='#FEFEFE'  align='center'>
 <tr>
  <td style='font-size:14px' bgcolor='#EFEFEF'><b>Non Select Query</b></td>
 </tr>
 <tr>
  <td style='font-family:courier new, courier, monaco, arial;font-size:14px'>$the_query</td>
 </tr>
 <tr>
  <td style='font-size:14px' bgcolor='#EFEFEF'><b>mySQL time</b>: $endtime</span></td>
 </tr>
</table><br />\n\n";
}
}

$this->query_count++;
        
        $this->obj['cached_queries'][] = $the_query;
        
        return $this->query_id;
    }
     function get_num_rows($query_id="") {
if ($query_id == "")
     {
     $query_id = $this->query_id;
     }
        return mysql_num_rows($query_id);
    }
。
?>

Answer 2

$query = "select id, name, fileName from InfoAttachment where infoId=$id and type='file'";
$res = $db->query($query);
$num_rows=$db->get_num_rows();
$num_rows可以得到正确的值！