Showing posts with label graphs. Show all posts
Showing posts with label graphs. Show all posts

Tuesday, 10 July 2012

How to do weighted average in Teradata?

As per the definiton of weighted average, its is the sum of datapoints*weights / sum of weights. Hence each data point contributes to the average according to the weight associated to it.

For example: Table Fact_Balance_01 has columns
Book_Balance
,Term

To calculate a weighted average Balance_Term , we have

Select
    Term
    ,Sum(Book_Balance * Term)/Sum(NULLIFZERO(Book_Value))
From
Fact_Balance_01
Group by 1

How it helps?

Over a period, it gives us a graph. Also called the SMA graph.
It can be effectively used to see where your business is headed.