Question

我从数据库中选择一个值，并希望在html页面中打印它。我试过这段代码：

$queryreg = mysql_query("SELECT available FROM hospital WHERE h_name='$hospital' ");
 $a=    $queryreg;  
 echo   $a;

但结果显示为＆＃34;资源ID＃7＆＃34;。请帮帮我

Answer 1

$queryreg = mysql_query("SELECT available FROM hospital WHERE h_name='$hospital' ");
    $queryreg = mysql_fetch_assoc($queryreg);
     $a=    $queryreg;  
     echo   $a['available'];

Answer 2

mysql_query()会在成功时返回资源。您必须使用mysql_fetch_row来检索返回与获取的行对应的数字数组并向前移动内部数据指针的值。

$queryreg = mysql_query("SELECT available FROM hospital WHERE h_name='$hospital' ");
if($queryreg)
{
      if(mysql_num_rows($queryreg) > 0)
      {
           $a = mysql_fetch_row($queryreg);  
           echo $a[0];
      }
      else
            echo "No records found.";
}
else
     echo "Cannot fetch records ".mysql_error();

如果从查询返回多行，您可以使用mysql_fetch_array()将结果行提取为关联数组，数字数组或两者

 $queryreg = mysql_query("SELECT available FROM hospital WHERE h_name='$hospital' ");
if($queryreg)
{
     if(mysql_num_rows($queryreg) > 0)
     {
          while($result = mysql_fetch_array($queryreg))
          {
               echo "<br>".$result[0];
          }
     }
     else
          echo "No records found.";
}
else
     echo "Cannot fetch records ".mysql_error();

如何从数据库

2 个答案: