> ## Documentation Index > Fetch the complete documentation index at: https://docs.narrative.io/llms.txt > Use this file to discover all available pages before exploring further. # Cross-Data Plane Query Errors > Resolve errors when queries reference data across multiple data planes NQL queries execute within a single [data plane](/concepts/primitives/data-planes). If your query references datasets that reside in different data planes, the query will fail. NQL cannot join or query across multiple data planes. All datasets referenced in a query must exist within the same data plane. ## Why this happens A data plane is the infrastructure where your data physically resides and where queries execute. Narrative's architecture separates data planes to enable: * **Data residency compliance** — Keep data in specific geographic or organizational boundaries * **Security isolation** — Maintain separate security perimeters for different data sources * **Infrastructure flexibility** — Run data planes on different platforms (Narrative-hosted, Snowflake, Spark) Because each data plane is an independent execution environment, the query engine cannot access data across data plane boundaries in a single query. For a deeper understanding of data plane architecture, see [Data Planes](/concepts/primitives/data-planes). ## Troubleshooting steps ### 1. Identify which datasets are in different data planes Review your query and identify all datasets referenced. In the Narrative platform: 1. Navigate to the dataset catalog 2. Check the data plane assignment for each dataset in your query 3. Note which datasets belong to different data planes ### 2. Modify your query Once you've identified the issue, you have two options: **Option A: Query datasets separately** Run separate queries against each data plane and combine results outside of NQL: ```sql theme={null} -- Query 1: Run against Data Plane A SELECT user_id, email, created_at FROM "companydata"."dataset_in_plane_a" WHERE ... -- Query 2: Run against Data Plane B SELECT user_id, email, created_at FROM "companydata"."dataset_in_plane_b" WHERE ... -- Combine results in your application ``` **Option B: Move data to a common data plane** If you need to join datasets frequently, consider: 1. Creating a materialized view that copies the necessary data to a single data plane 2. Working with your Narrative representative to consolidate datasets Data movement between data planes may have compliance implications. Consult your data governance team before moving data. ## Related content Understand where your data lives and is processed How queries flow from submission through execution How Narrative orchestrates across data planes Overview of common NQL errors