Added Scalar UDF Demo

Author: pmasl

samples/features/intelligent-query-processing/Intelligent QP Demos WideWorldImportersDW Public Preview - Scalar UDF Inlining.sql

@@ -0,0 +1,65 @@
+-- ******************************************************** --
+-- Scalar UDF Inlining
+
+-- See https://aka.ms/IQP for more background
+
+-- Demo scripts: https://aka.ms/IQPDemos 
+
+-- Demo uses SQL Server 2019 Public Preview and also works on Azure SQL DB
+
+-- Email IntelligentQP@microsoft.com for questions\feedback
+-- ******************************************************** --
+USE WideWorldImportersDW;
+GO
+
+ALTER DATABASE WideWorldImportersDW 
+SET COMPATIBILITY_LEVEL = 150;
+GO
+
+ALTER DATABASE SCOPED CONFIGURATION 
+CLEAR PROCEDURE_CACHE;
+GO
+/*
+Adapted from SQL Server Books Online
+https://docs.microsoft.com/en-us/sql/relational-databases/user-defined-functions/scalar-udf-inlining?view=sqlallproducts-allversions 
+*/
+CREATE OR ALTER FUNCTION 
+	dbo.customer_category(@CustomerKey INT) 
+RETURNS CHAR(10) AS
+BEGIN
+  DECLARE @total_amount DECIMAL(18,2);
+  DECLARE @category CHAR(10);
+
+  SELECT @total_amount = 
+	SUM([Total Including Tax]) 
+	FROM [Fact].[OrderHistory]
+	WHERE [Customer Key] = @CustomerKey;
+
+  IF @total_amount < 500000
+    SET @category = 'REGULAR';
+  ELSE IF @total_amount < 1000000
+    SET @category = 'GOLD';
+  ELSE 
+    SET @category = 'PLATINUM';
+
+  RETURN @category;
+END
+GO
+
+-- Before (show actual query execution plan for legacy behavior)
+SELECT TOP 100
+		[Customer Key], [Customer],
+       dbo.customer_category([Customer Key]) AS [Discount Price]
+FROM [Dimension].[Customer]
+ORDER BY [Customer Key]
+OPTION (RECOMPILE,USE HINT('DISABLE_TSQL_SCALAR_UDF_INLINING'));
+
+-- After (show actual query execution plan for Scalar UDF Inlining)
+SELECT TOP 100
+		[Customer Key], [Customer],
+       dbo.customer_category([Customer Key]) AS [Discount Price]
+FROM [Dimension].[Customer]
+ORDER BY [Customer Key]
+OPTION (RECOMPILE);
+
+

samples/features/intelligent-query-processing/readme.md

@@ -12,5 +12,6 @@ Demos (with more on the way!):
 - [Batch mode on rowstore](Intelligent%20QP%20Demos%20WideWorldImportersDW%20Public%20Preview%20-%20Batch%20Mode%20on%20Rowstore.sql) 
 - [APPROX_COUNT_DISTINCT](Intelligent%20QP%20Demos%20WideWorldImportersDW%20Public%20Preview%20-%20APPROX_COUNT_DISTINCT.sql) 
 - [Table variable deferred compilation](Intelligent%20QP%20Demos%20WideWorldImportersDW%20Public%20Preview%20-%20TVDC.sql) 
+- [Scalar UDF Inlining](Intelligent%20QP%20Demos%20WideWorldImportersDW%20Public%20Preview%20-%20Scalar%20UDF%20Inlining.sql)
 
 Email IntelligentQP@microsoft.com if questions in the meantime.