php的查询功能（怎么通过查询条件获取相应表的字段）

php的查询功能（如何通过查询条件获取相应表的字段）

//获得连接
$db = mysql_connect("localhost", "root", "root") or die(mysql_error());
//echo "Connected to MySQL
";
//连接数据库
mysql_select_db("test") or die(mysql_error());
//echo "Connected to Database";

    //查询数据，并用表格显示出来  
	@$checked = $_POST['checked'];
	@$result = mysql_query("select * from books",$db);
    echo "\n";                                      
    echo "




			 ";                                                     
    echo "\n";                                                 
    //循环遍历                                                          
      while ($myrow = mysql_fetch_row($result)){ 
	          printf("



", $myrow[0], $myrow[1],$myrow[2],$myrow[3]);
            }                                                               
         echo "
	         
isbn
			 
author
			 
title
			 
price
			               
%s
						   
%s
						   
%s
						   
%s
\n";
?>

------解决方案--------------------
result = mysql_query("select * from books where checked=‘$checked’ ");
------解决方案--------------------
if(isset($_POST['checked'])){
@$result = mysql_query("select * from books",$db);
echo "\n";
echo "




";
echo "\n";
//循环遍历

isbn

author

title

price