Php unlimited classification how to implement using concat

This article describes how to use concat for php unlimited classification. For more information, see

This article describes how to use concat for php unlimited classification. For more information, see

-- 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', 'website'); insert into 'category' VALUES (2, '0-1', 'linux OS '); INSERT INTO 'category 'values (3, '0-1', 'apache Server '); insert into 'category 'values (4, '0-1', 'mysql database'); insert into 'category 'values (5, '0-1 ', 'php scripting language '); insert into 'category' VALUES (6, '0-1-2', 'linux system example'); insert into 'category' VALUES (7, '0-1-2 ', 'linux Network Technology'); insert into 'category 'values (8, '0-1-2 ', 'linux Security Basics '); insert into 'category 'values (9, '0-1-2-7 ', 'linux LAMP'); insert into 'category 'values (10, '0-1-3-10 ', 'apache Server ');

Here, the-link symbol of catpath is not fixed and can be selected, and other special symbols.

Ii. PHP code implementation

<? $ 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) {// first display method // $ space = str_repeat ('', count (explode ('-', $ row ['abspath'])-1); // echo $ space. $ row ['name'].'
'; * // Second display method $ space = str_repeat ('', count (explode ('-', $ row ['abspath'])-1 ); $ option. =''. $ Space. $ row ['name'].'';} Echo''. $ Option .'';?>

The MySQL concat function can be used to connect one or more strings.

Select concat ('yan ', 'pei', 'pan ') select 'id', 'name', concat ('id','-', 'name') as iname