Unlimited classification of PHP using concat

What is the unlimited classification of concat in PHP ?? I. Database Design :?? ---- Tablestructurefortable 'Category '-- CREATETABLE 'Category' ('id' int (11) NOTNULLauto_increment, 'catpath' varchar (255) defaultNUL PHP uses the unlimited classification of concat

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I. database design:

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-- 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 ');

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

II. PHP code implementation:

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

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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

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Association:

Simple unlimited classification class category, menus, jquery tree view?

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