How to Make a Weighted Average

[sam8]

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The Problem

We want to make a weighted average.
 

The Solution

In this example, we want to create a very basic customer health comparison by taking the average of each customer's order prices and weighting them by how recently each order was placed.

First, we give each order a numerical weight, giving a higher weight to more recent orders:

dimension: weight {
  type: number
  sql:
    CASE
      WHEN ${days_since_order} < 30 THEN 3
      WHEN ${days_since_order} < 60 THEN 2
      ELSE 1
    END ;;
}

From here, we can calculate a weighted price by multiplying the weight by the price, and finally creating the weighted average of this weighted price:

dimension: weighted_price {
  type: number
  sql: ${sale_price} * ${weight} ;;
}

measure: weighted_average {
  type: number
  sql: sum(${weighted_price})/sum(${weight}) ;;
 }

The result is a weighted average, which focuses on recent orders: