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Update scalar UDF inlining requirements in documentation #10337

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Update scalar UDF inlining requirements in documentation #10337

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Update scalar UDF inlining requirements in documentation
simonsabin May 22, 2026
705a24f
Clarify rules for using scalar UDFs in queries
simonsabin May 22, 2026
efc0b15
Potential fix for pull request finding
simonsabin May 22, 2026
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3 changes: 2 additions & 1 deletion docs/t-sql/statements/create-function-sql-data-warehouse.md
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Expand Up @@ -26,7 +26,8 @@ monikerRange: ">=aps-pdw-2016 || =azure-sqldw-latest || =fabric"
> Scalar UDFs are a preview feature in Fabric Data Warehouse.

> [!IMPORTANT]
> In Fabric Data Warehouse, [scalar UDFs must be inlineable](#scalar-udf-inlining) for use with `SELECT ... FROM` queries on user tables, but you can still create functions that aren't inlineable. Scalar UDFs that are not inlineable work in limited number of scenarios. You can check [whether a UDF can be inlined](#check-whether-a-scalar-udf-can-be-inlined).
> In Fabric Data Warehouse, a scalar UDF used in a query must follow the [rules to allow inlining](../../relational-databases/user-defined-functions/scalar-udf-inlining.md#inlineable-scalar-udf-requirements). Otherwise, you will get the error `Scalar UDF execution is currently unavailable in this context.`.
Scalar UDFs that cannot be inlined can be used outside of a query. You can check [whether a UDF can be inlined](#check-whether-a-scalar-udf-can-be-inlined).
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@SrdjanMatin SrdjanMatin Jun 1, 2026

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@simonsabin : Thank you.

Microsoft Fabric Data Warehousing has been leveraging Scalar UDF inlining, and will continue to do so. Inlining remains an important aspect, albeit scope of inlining is changing and changing beyond what's available in Sql Server/DB. Meaning, referencing pure to scalar udf inlining requirements is becoming less relevant and I don't see it should be forefront of the documentation.

E.g. with next increment, Customers of Fabric Data Warehouse can inline UDFs with while loops, or use computation based UDFs together with CTEs.


A user-defined function is a [!INCLUDE [tsql](../../includes/tsql-md.md)] routine that accepts parameters, performs an action, such as a complex calculation, and returns the result of that action as a value. Scalar functions return a scalar value, such as a number or string. User-defined table-valued functions (TVFs) return a table.

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