Many-to-many MySql relation: how to retrieve all related entries in one query?

Suppose there are 3 Table 1) Products , 2)Category & 3)Pro_Cat :- Many to Many RelationShip B/w Products & Category Table :-

1) Products Table :-                                  

Product_Id	Product_Name
1	Samsung
2	Relience
3	Micromax

2) Category Table :-

Category_Id	Category_Name
1	Mobile
2	Retails
3	Usb

3) Product_Category Many into Many Relationship Table :-

Product_Id	Category_Id
1	1
2	1
2	2
3	1
3	3

Result Query :-

SELECT
  product.product_name,
  GROUP_CONCAT(category.category_name) AS category_name
FROM product,category,pro_cat
Where product.product_id = pro_cat.product_id
and category.category_id = pro_cat.category_id
GROUP BY product.product_id;

Result :-

Product_Name	Category_Names
Samsung	Mobile
Relience	Mobile,Retails
Micromax	Mobile ,Usb