Aggregate

Group rows by one or more columns and compute summary values per group.

When to use this

• You want a total, average, or count per category, for example total quantity per product, average cost per location, or count of orders per customer
• You want to roll up a fine-grained dataset to a coarser level before feeding it downstream

What you need

• One upstream data source wired into the Aggregate node
• The columns to summarize, and optionally the columns to group by

Parameters

Set in the side panel:

Setting	Description
Group By	Optional. Column names; rows that share the same values across these columns form a group. Leave it empty to summarize the whole table into one row.
Aggregations	One or more column · function pairs. The result keeps the column's name: a Sum of quantity is a column called quantity. For Count, the column is the name of the new column that holds the count.

Aggregation functions

Function	What it does
Sum	Total of the column's numeric values in the group
Average	Mean of the column's numeric values in the group
Count	Number of rows in the group
Min	Smallest numeric value in the group
Max	Largest numeric value in the group
First	Value from the first row in the group. A blank cell is a value, so a blank in the first row gives a blank result

What you get

One row per group, with one column per Group By field and one column per aggregated column. With no Group By, one row for the whole table.

Workflow wiring

flowchart LR
    n1["Import Data (orders.csv)"] --> n2["Aggregate (group by product, sum quantity)"]
    n2 --> n3["Save Data (product_totals)"]

Common mistakes

• Using Sum, Average, Min, or Max on a column that has non-numeric values. Those values drop out of the group and the total comes back quietly low. Once half a column will not read as numbers, the run says so in the Execution Report, naming the column and a few of the offending values. Below that it says nothing
• Expecting Count to skip blanks. It counts every row in the group and reads no column's values
• Forgetting to add an Aggregation. Without one, every group collapses to a single Group By row with no summary columns
• Giving one column two functions, such as Sum and Average of quantity. Both results are written to the quantity column and only the last one is kept. Use one function per column
• Naming a Count after a column you also aggregate or group by. The two share one column and only one of them is kept

Messages this node can show

• Aggregate column not in input
• Aggregated column not numeric

A run gives this node 5 minutes. A node that takes longer stops with Time limit reached.

Like every node, it can also stop on the checks before a run and the run's limits.