PHP使用concatの無限分類

 
一、データベース設計:
 
 

-- 
-- Table structure for table `category`
-- 

CREATE TABLE `category` (
  `id` int(11) NOT NULL auto_increment,
  `catpath` varchar(255) default NULL,
  `name` varchar(255) default NULL,
  PRIMARY KEY  (`id`)
) ENGINE=MyISAM  DEFAULT CHARSET=utf8 AUTO_INCREMENT=11 ;

-- 
-- Dumping data for table `category`
-- 

INSERT INTO `category` VALUES (1, '0', '    ');
INSERT INTO `category` VALUES (2, '0-1', 'Linux OS');
INSERT INTO `category` VALUES (3, '0-1', 'Apache   ');
INSERT INTO `category` VALUES (4, '0-1', 'MySQL   ');
INSERT INTO `category` VALUES (5, '0-1', 'PHP    ');
INSERT INTO `category` VALUES (6, '0-1-2', 'Linux     ');
INSERT INTO `category` VALUES (7, '0-1-2', 'Linux     ');
INSERT INTO `category` VALUES (8, '0-1-2', 'Linux     ');
INSERT INTO `category` VALUES (9, '0-1-2-7', 'Linux LAMP');
INSERT INTO `category` VALUES (10, '0-1-3-10', 'apache Server');

 
 
ここではcatpathの-リンク記号は固定されていないので、選択できます.などの特殊記号.二、PHPコード実現:
 
 

<?
$conn = mysql_connect ( 'localhost', 'root', 'root' );
mysql_select_db ( 'test', $conn );
mysql_query ( 'set names UTF8' );
$sql = "select id,concat(catpath,'-',id) as abspath,name from category order by abspath";
$query = mysql_query ( $sql );
while ( $row = mysql_fetch_array ( $query ) ) 
{
    //       
    //$space = str_repeat ( '&nbsp;&nbsp;&nbsp;&nbsp;', count ( explode ( '-', $row ['abspath'] ) ) - 1 );
    //echo $space . $row ['name'] . '<br>';*/
    
    //       
    $space = str_repeat ( '&nbsp;&nbsp;&nbsp;&nbsp;', count ( explode ( '-', $row ['abspath'] ) ) - 1 );
    $option .= '<option value="' . $row ['id'] . '">' . $space . $row ['name'] . '</option>';
}
echo '<select name="opt">' . $option . '</select>';
?>

 
MySQL concat関数は、1つ以上の文字列select concat('顔','培','攀')select`id`,`name`,concat(`id`,'-',`name`)as inameに接続できます.
 
 
 
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