The text explores the process of joining data from multiple NoSQL documents, focusing on MongoDB and Couchbase, two popular NoSQL databases. It compares MongoDB's use of the $lookup operator within aggregation queries to perform left outer joins, noting that additional steps such as unwinding arrays can complicate the process, especially for complex queries. In contrast, Couchbase's N1QL query language is presented as more intuitive and efficient, allowing for straightforward SQL-like JOIN operations and ease in managing complex queries. The text suggests that while MongoDB's $lookup is manageable for simple joins, Couchbase's N1QL provides a more user-friendly approach for handling intricate data joining tasks.