Funtion of Sorting an Array using Php

$arr = array(1,7,6,8,4,5,2);

function sg_array_sort($arr) {
    for($i=1;$i      for($j=$i-1;$j>=0;$j--) {   
         if($arr[$i] < $arr[$j]) {
            $temp = $arr[$i];
            $arr[$i]= $arr[$j];
            $arr[$j] = $temp;
            $i = $j;
         } 
      }
    }
}

$sort_arr =  sg_array_sort($arr);

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