Your understanding of cardinality and its influence on the type of join to use in Qlik is mostly correct. Here’s a more detailed explanation based on my understanding:
1-1 Cardinality: If there’s a (1-1) relationship between the tables, you can use ApplyMap. It’s a more efficient way to replace field values based on a mapping table.
1-m Cardinality: In a (1-m) relationship, if you want to associate with more than two rows, you can indeed use a LEFT JOIN. This will ensure all records from the “one” table and any matching records from the “many” table are included.
m-1 Cardinality: In a (m-1) relationship, a RIGHT JOIN can be used. This will ensure all records from the “many” table and any matching records from the “one” table are included.
However, it’s important to note that Qlik also provides the JOIN prefix which performs a natural join of two tables based on their common fields. The JOIN prefix can be used instead of LEFT JOIN or RIGHT JOIN if you want to combine rows from both tables that have an exact match in the specified fields.
Hope this helps!
