MySQL加入显示类别，子类别和子类别

Question

我有三个表格：类别，子类别和子类别。

我想显示按照以下格式列表：

dvds 
cds 
cds > pop 
cds > blues 
cds > new age 
cds > new age > whale noises 
books 
books > cowboys 
books > zombies

我已经成功除了自己的类别的名称，以显示一切，当他们有了孩子，如什么，我得到的是：

dvds 
cds > pop 
cds > blues 
cds > new age > whale noises 
books > cowboys 
books > zombies

上面所列内容缺少CD和书籍类型，加上CDS>新时代的子类别。

我使用的查询是：

SELECT 
    c.name AS c_name, 
    sc.name AS sc_name, 
    ssc.name AS ssc_name 
FROM 
    categories c 
LEFT JOIN 
    subcategories sc 
    ON c.id = sc.category_id 
LEFT JOIN 
    subsubcategories ssc 
    ON sc.id = ssc.subcategory_id 

任何帮助，将不胜感激！

Answer 1

SELECT * 
FROM (
     SELECT DISTINCT 
       c.name AS c_name, 
       sc.name AS sc_name, 
       ssc.name AS ssc_name 
     FROM categories c 
     LEFT JOIN 
       subcategories sc 
     ON  c.id = sc.category_id 
     LEFT JOIN 
       subsubcategories ssc 
     ON  sc.id = ssc.subcategory_id 
     GROUP BY 
       c.name, sc.name, ssc.name WITH ROLLUP 
     HAVING c_name IS NOT NULL 
     ) q 
ORDER BY 
     c_name, sc_name, ssc_name