How does the KEEP operation function in relation to tables in Qlik Sense?

The KEEP operation in Qlik Sense allows you to manage relationships between tables while keeping the tables themselves separate. It functions similarly to a JOIN, where the resulting dataset is based on the matching fields from both tables while maintaining their distinct existence.

When you use the KEEP operation, Qlik Sense effectively filters the rows of each table, so only the entries that have matching keys in both tables are retained for analysis. This means that while the data is linked logically, the original tables remain independent, enabling you to handle complex data scenarios and maintain clarity and separation.

This operation is particularly useful when you want to analyze data that has overlapping keys without the complications that arise from fully merging the tables. By establishing a KEEPs relationship instead of merging, you preserve the original data structure and avoid issues related to duplicated rows or loss of data integrity that can occur with a traditional JOIN.

Understanding this behavior is crucial for data architects who need to ensure that transformations do not inadvertently merge tables when they only want to create associations between them for analytical purposes.