Append Data Extension

Append Data Extensions allow you to combine the results of multiple Selection Criteria into a single Target Data Extension. This feature functions like a standard SQL UNION statement, where each source is set up in a different tab and acts as an independent query.

Append Data Extensions is especially useful when you need to merge data from multiple sources that share a similar structure. For example, you can use it to combine email addresses from various contact lists or merge information from different retail branches into one Master Data Extension.

To set this up, click the + Add new source icon, which allows you to define completely different data sources and filters for each independent tab before mapping them to your final Target Data Extension. Currently, there is no limit on the number of tabs/sources you can add.

When mapping, you need to switch between the sources/tabs and ensure to map the necessary Available DE fields to the Target DE fields.

This video shows a detailed example of Append Data Extensions and walks through the whole functionality.

Depending on the results you are looking for, you can choose to do a matching A with all B relationship (FULL OUTER JOIN in SQL) or use Append Data Extensions.

In general, when trying to merge data from multiple Source Data Extension (input sources) into one Target Data Extension (output source), Append Data Extensions is preferable.

To see the difference in the results, this example scenario starts with two Data Extensions that contain customer and lead information.

This will create rows with data from both Data Extensions based on one or more matching columns. In this example, the Data Extensions will match on Id. Here's what the results will look like after doing a Match All Customers with All Leads (Full Outer Join).

This action will bring all the rows of each Data Extension into one new Data Extension. This is what the results will look like after using Append Data Extensions.