Using N1QL Subquery Expressions to Query Over Nested Couchbase Documents

Couchbase 5.0 introduces subquery expressions in its N1QL query language, allowing developers to use subqueries within generic expressions for more flexibility and functionality compared to previous versions. This feature enables the use of subqueries for aggregation, existence checks, and other operations, providing a way to simplify complex queries while maintaining performance. Subquery expressions can be used in various clauses such as `EXISTS`, `MERGE`, and `LET` to achieve specific results, offering more control over query logic without compromising performance. The new feature is currently available through developer builds, with production-ready versions expected in the future.