SQL

SQLServerCentral Article

How to filter non-existing records in SQL

  • Article

Introduction Developing predefined reports in addition to all the ad-hoc queries have been a part of my daily activities. Often I find my stakeholders asking me to prepare reports in which they want to know something that has never happened. It might sound strange, but yeah, that's what their point of concern is all about. […]

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2021-11-26 (first published: )

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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

5,088 reads

SQLServerCentral Article

Optimize Your SQL by Reformulating the Spec

  • Article

As SQL developers, we tend to think of performance tuning in terms of crafting the best table indices, avoiding scalar and table valued functions, and analyzing query plans (among other things). But sometimes going back to the spec and applying some properties of elementary math can be the best way to begin to improve performance of SQL queries which implement mathematical formulas. This article is a case study of how I used this technique to optimize my SQL implementation of the Inverse Simpson Index.

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2021-05-07 (first published: )

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Question of the Day

The Tightly Linked View

I try to run this code on SQL Server 2022. All the objects exist in the database.

CREATE OR ALTER VIEW OrderShipping
AS
SELECT cl.CityNameID,
       cl.CityName,
       o.OrderID,
       o.Customer,
       o.OrderDate,
       o.CustomerID,
       o.cityId
 FROM dbo.CityList AS cl
 INNER JOIN dbo.[Order] AS o ON o.cityId = cl.CityNameID
GO
CREATE OR ALTER FUNCTION GetShipCityForOrder
(
    @OrderID INT
)
RETURNS VARCHAR(50)
WITH SCHEMABINDING
AS
BEGIN
    DECLARE @city VARCHAR(50);
    SELECT @city = os.CityName
    FROM dbo.OrderShipping AS os
    WHERE os.OrderID = @OrderID;
    RETURN @city;
END;
go
What is the result?

See possible answers