How to calculate the sum of values in a tree using SQL

Question

I need to sum points on each level earned by a tree of users. Level 1 is the sum of users\' points of the users 1 level below the user. Level 2 is the Level 1 points of the

Answer 1

You can write a simple recursive function to do the job. My MSSQL is a little bit rusty, but it would look like this:

CREATE FUNCTION CALC
(
@node integer,
)
returns 
(
@total integer
)
as
begin
    select @total = (select node_value from yourtable where node_id = @node);

    declare @children table (value integer);
    insert into @children   
    select calc(node_id) from yourtable where parent_id = @node;

    @current = @current + select sum(value) from @children;
    return
end