Using other query results is an advanced method about how to restrict other queries based on other types of operands. This concept is similar to the subquery concept with some differences:
The query doesn't generate SQL; rather, it uses the results returned by other query results (could be seen as a local function rather than a database function).
Query results from other universes can be used (in a subquery, it is limited to the same universe).
Other data providers such as Excel can be used too.
The number of rows that the main query can process from the inner query is limited to 1,000 rows (the 1,000 value limit is a common limit for most of the databases; however, in some cases, it's possible to extend it to 3,000 or even 10,000 rows. It's advised to consult your database administrator or BI support team in case you require more than 1,000 values).