Phil Jacobs

Phil began his career as a Member of the Technical Staff at Bell Labs. He worked in IT at Moody's Investors Service for 27 years supporting Structured Finance, his last position being Vice President - Senior Database Developer, and he is currently a senior SQL development engineer at Dynamic Healthcare Solutions. Phil holds a Sc.B. in Computer Science from Brown University and a M.S. in Computer Science from Purdue University.

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SQLServerCentral Article

Optimize Your SQL by Reformulating the Spec

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 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