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

5,178 reads

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

21,759 reads

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Question of the Day

ORDER BY alias

There is a table tmp_tab:

CREATE TABLE tmp_tab (
id int,
val int
);
INSERT INTO tmp_tab VALUES
(1, 1),
(2, NULL),
(3, 3),
(4, 4),
(5, 5);
You want to order the rows ids by the following expression:
    ISNULL(val, id) + 1
Which of the following queries produces the expected ordering and why? (Select all correct)

See possible answers