downline count

[iamkundan]

hey, i am newbie , need help in creating a php script which can count the no. of members in a binary downline, the fields in the database are like this:

 

id    member_name      ref_id

1      kundan                    0

2      rahul                        1

3    deepak                    2

4    chandan                    2

5    avi                            3

6    ajit                            3

7    punit                        4

8    sunil                        4

 

the tree will grow to abt ten thousands of members, i'm trying to work it out by using recursive functions(using a while loop), and i am able to print the downline as a list, but the problem is that i've to calculate the no. of members. can anyone help...