The function of a Merge node is to take multiple input records and create a single output record containing all or some of the input fields. This is a useful operation when you want to merge data from different sources, such as internal customer data and purchased demographic data.
You can merge data in the following ways.
- Merge by Order concatenates corresponding records from all sources in the order of input until the smallest data source is exhausted. It is important if using this option that you have sorted your data using a Sort node.
- Merge using a Key field, such as
Customer ID, to specify how to match records from one data source with records from the other(s). Several types of joins are possible, including inner join, full outer join, partial outer join, and anti-join.
- Merge by Condition means that you can specify a condition to be satisfied for the merge to take place. You can specify the condition directly in the node, or build the condition using the Expression Builder.
- Merge by Ranked Condition is a left sided outer join in which you specify a condition to be satisfied for the merge to take place and a ranking expression which sorts into order from low to high. Most often used to merge geospatial data, you can specify the condition directly in the node, or build the condition using the Expression Builder.