When is using an OUTER KEEP meaningful in Qlik Sense?

Using an OUTER KEEP in Qlik Sense is particularly meaningful when no rows are reduced as a result of the operation. This means that the OUTER KEEP function is used to ensure that the rows in one table are not filtered out or reduced in quantity due to the association with another table.

In cases where you want to maintain all rows from one of the tables regardless of whether there are matching rows in the other table, OUTER KEEP becomes crucial. It allows for maintaining the integrity of the dataset from which you want to preserve all records.

For instance, if you have a main table of transactions and you want to overlay some additional information from a related table without losing any of the original transaction records even if there is no associated data in the second table, OUTER KEEP would be the appropriate function to utilize.

This behavior of keeping all rows and avoiding reductions in data is fundamental to certain analytical scenarios where you need to ensure that every record from the primary dataset remains accessible for subsequent analysis or reporting.