Cross Warehouse Queries in Fabric – Query Across Warehouses with T-SQL | Microsoft Fabric Tutorial

Cross Warehouse Queries in Fabric – Query Across Warehouses with T-SQL

In Microsoft Fabric, you can execute cross warehouse queries to join or fetch data from multiple warehouses within the same workspace using standard T-SQL. This is useful for creating unified reports, performing analytics across departments, or consolidating data silos.

📘 What Are Cross Warehouse Queries?

Allows querying across two or more Fabric Warehouses
Supports read-only access to external warehouse tables
Uses Linked Server-style 3-part or 4-part naming convention
Enables you to join data without ETL duplication

✅ Prerequisites

Both warehouses must be in the same workspace
You must have read permissions on the external warehouse
SQL editor must be used within a Fabric Warehouse context

🧪 Example Query

Assume you are connected to SalesWarehouse and want to pull data from FinanceWarehouse:

SELECT o.OrderID, o.CustomerID, f.Balance
FROM dbo.Orders o
JOIN [FinanceWarehouse].[dbo].[CustomerAccounts] f
  ON o.CustomerID = f.CustomerID;

This query joins the Orders table from the current warehouse with the CustomerAccounts table from the FinanceWarehouse.

🎯 Use Cases

Central reporting across multiple business domains
Joining data from regional and global warehouses
Performing data validation across systems
Avoiding ETL and staging for short-term analytics

⚠️ Limitations

Write operations (INSERT, UPDATE) are not allowed on external warehouse tables
Performance depends on table sizes and Fabric capacity
Cross queries are scoped to the same workspace only
Only supported in SQL Editor, not in Dataflow Gen2 or Power BI visuals directly

💡 Tips for Efficient Cross Warehouse Queries

Use TOP or WHERE clauses to limit data early
Apply indexing strategies on foreign keys in both warehouses
Use SELECT ... INTO to materialize external data into local staging tables if needed repeatedly

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