需要幫助的SQL查詢

Question

這是我的表結構：

 
id id_parent id_origin level name 
1 0 1 1 PHP 
2 0 2 1 Javascript 
3 0 3 1 SMARTY 
4 0 4 1 HTML 
5 1 1 2 Basic 
6 1 1 2 Date & Math Function 
8 2 2 2 DOM 
9 5 1 3 Introduction 
10 5 1 3 Session & Cookies 
12 2 2 2 Introduction 
13 4 4 2 Basic Structure 
14 6 1 3 PHP Date Function 
16 3 3 2 Basic Syntax 
26 4 4 2 Table 

我想導致類似下面的格式

 
Myfinalstr 
----------- 
PHP 
PHP->Basic 
PHP->Basic->Introduction 
PHP->Basic->Session & Cookies 
PHP->Date & Match Function 
PHP->Date & Match Function->PHP Date Function 
Javascript 
Javascript->DOM 
Javascript->Introduction 
SMARTY 
SMARTY->Basic Syntax 
HTML 
HTML->Basic Structure 
HTML->Table 

Answer 1

下心不是一個完整的解決方案，但它讓你開始：

示例存儲過程調用

mysql> call chapter_hier(1); 
+----+----------------------+-----------+----------------------+-------+ 
| id | category_name  | id_parent | parent_category_name | depth | 
+----+----------------------+-----------+----------------------+-------+ 
| 1 | PHP     |  NULL | NULL     |  0 | 
| 5 | Basic    |   1 | PHP     |  1 | 
| 6 | Date & Math Function |   1 | PHP     |  1 | 
| 9 | Introduction   |   5 | Basic    |  2 | 
| 10 | Session & Cookies |   5 | Basic    |  2 | 
| 14 | PHP Date Function |   6 | Date & Math Function |  2 | 
+----+----------------------+-----------+----------------------+-------+ 
6 rows in set (0.00 sec) 

$result = $conn->query(sprintf("call chapter_hier(%d)", 1)); 

全部腳本和測試數據

drop table if exists chapters; 
create table chapters 
(
id smallint unsigned not null primary key, 
name varchar(255) not null, 
id_parent smallint unsigned null, 
key (id_parent) 
) 
engine = innodb; 

insert into chapters (id, name, id_parent) values 
(1,'PHP',null), 
(2,'Javascript',null), 
(3,'SMARTY',null), 
(4,'HTML',null), 
(5,'Basic',1), 
(6,'Date & Math Function',1), 
(8,'DOM',2), 
(9,'Introduction',5), 
(10,'Session & Cookies',5), 
(12,'Introduction',2), 
(13,'Basic Structure',4), 
(14,'PHP Date Function',6), 
(16,'Basic Syntax',3), 
(26,'Table',4); 


drop procedure if exists chapter_hier; 
delimiter # 

create procedure chapter_hier 
(
in p_id smallint unsigned 
) 
begin 

declare v_done tinyint unsigned default 0; 
declare v_depth smallint unsigned default 0; 

create temporary table hier(
id_parent smallint unsigned, 
id smallint unsigned, 
depth smallint unsigned default 0 
)engine = memory; 

insert into hier select id_parent, id, v_depth from chapters where id = p_id; 
create temporary table tmp engine=memory select * from hier; 

/* http://dev.mysql.com/doc/refman/5.0/en/temporary-table-problems.html */ 

while not v_done do 

    if exists(select 1 from chapters c 
     inner join tmp on c.id_parent = tmp.id and tmp.depth = v_depth) then 

     insert into hier select c.id_parent, c.id, v_depth + 1 from chapters c 
      inner join tmp on c.id_parent = tmp.id and tmp.depth = v_depth; 

     set v_depth = v_depth + 1;   

     truncate table tmp; 
     insert into tmp select * from hier where depth = v_depth; 

    else 
     set v_done = 1; 
    end if; 

end while; 

select 
c.id, 
c.name as category_name, 
p.id as id_parent, 
p.name as parent_category_name, 
hier.depth 
from 
hier 
inner join chapters c on hier.id = c.id 
left outer join chapters p on hier.id_parent = p.id 
order by 
hier.depth; 

drop temporary table if exists hier; 
drop temporary table if exists tmp; 

end # 

delimiter ; 

希望它能幫助:)