User Defined Function (UDF)

SQLServerCentral Article

A User-Defined Function returns more rows

  • Article

The Problem Recently, while working with one of my clients, I came across a script in which I had to introduce a scalar User-Defined Function in the SELECT statement. The SELECT used to return around 750K records. However, after introducing the UDF, the row count significantly increased to 826K. There were no other changes made […]

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2019-10-14

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Technical Article

Understand when to use user-defined functions in SQL Server

  • Article

In the simplest terms, a user-defined function (UDF) in SQL Server is a programming construct that accepts parameters, does work that typically makes use of the accepted parameters, and returns a type of result. This article will cover two types of UDFs: table-valued and scalar-valued.

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2007-12-12

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SQLServerCentral Article

Complex Computed Columns

  • Article

Computed columns in SQL Server 2000 allow you to have a calculated value available easily in a query. However by using a function instead of a simple formula you can build some very interesting solutions. New author Tim Chapman brings us a look at this technique.

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2006-05-09

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Question of the Day

The Empty Aggregate

I have this table in a SQL Server 2025 database:

CREATE TABLE [dbo].[CustomerOrder]
(
[OrderID] [int] NULL,
[CustomerID] [int] NULL,
[total] [money] NULL
) ON [PRIMARY]
GO
What is returned from this code? (answers are for the sum and then the count)
SELECT SUM(total) AS sum,
       COUNT(total) AS count
FROM dbo.CustomerOrder;



See possible answers