🔷 Running Aggregations (Aggregation-based Accumulations)

🔍 Definition

This feature is used to:

➡️ Calculates running aggregations
➡️ Can be used for more than one field at a time
➡️ Supports various statistical functions


👉 So this is an advanced version of:

• Accumulator (one field)
• Accumulations (multi field)

⚙️ Parameter

Format:

Agg_function1:Field_Name1,Agg_function2:Field_Name2,...

🎯 List of Agg Functions

    Function        Information
    -------------------------------
    sum             cumulative total
    average         running average
    min	minimum     running value
    max	maximum     running value
    stdev           standard deviation
    median          walking median

📌 Example Parameters

    sum:views,average:likes,max:views

It means:

• running sum for views
• running average for likes
• running max for views

📥 Input & 📤 Output Input

• All fields from previous data

Output

• All input fields
  ➕ new fields:

  running1, running2, running3, ...
  

The number of fields depends on the number of aggregations.

🧠 How it works

Sample Data:

    id	views	likes
    -----------------
    1	10	2
    2	20	4
    3	30	6

Parameter:

    sum:views,average:likes

Output:

    id	views	likes	running1 (sum views)	running2 (avg likes)
    -----------------------------------------------------------------
    1	10	2	10                      2.0
    2	20	4	30                      3.0
    3	30	6	60                      4.0