The Couchbase Query and Analytics services are two options for querying documents using SQL. The Query service is used for data manipulation within application logic, while the Analytics service is used for reports, analysis, and dashboards. The Query service is more efficient for short, operational queries that retrieve or manipulate smaller amounts of data, whereas the Analytics service is better suited for longer, complex queries that process large amounts of data. Key differences between the two services include their ability to support SELECT, INSERT, UPDATE, DELETE, MERGE operations (Query) and only SELECT operations (Analytics). The Query service performs well on operational queries with simple filters, while the Analytics service excels at more complex queries involving aggregations, joins, and window functions. In a 3-node Couchbase cluster environment, the Analytics service outperforms the Query service in most cases, especially for queries that require joins or aggregations. However, the performance gap narrows when adding Window functions to the query. Understanding when to use each service is crucial for optimizing data access and analysis in Couchbase applications.