SQL Trivia – Difference between COUNT(*) and COUNT(1)

Yesterday I was having a discussion with one of the Analyst regarding an item we were going to ship in the release. And we tried to check and validate the data if it was getting populated correctly or not. To just get the count-diff of records in pre & post release I used this Query:

To my surprise he mentioned to use COUNT(1) instead of COUNT(*), and the reason he cited was that it runs faster as it uses one column and later uses all columns. It was like a weird feeling, what to say… and I just mentioned “It’s not, and both are same”. He was adamant and disagreed with me. So I just kept quite and keep on using COUNT(*) 🙂

But are they really same or different? Functionally? Performance wise? or by any other means?

Let’s check both of them.

The MSDN BoL lists the syntax as

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Published by Mustafa EL-Masry

I am Microsoft database consultant working as a Database administrator for more than +10 Years I have very good knowledge about Database Migration, Consolidation, Performance Tuning, Automation Using T-SQL, and PowerShell and so many other tasks I do it in multiple customers here in KSA and as of now, I am working in Bank Albilad managing the core banking system that is hosted in SQL Server Database 8 TB. Also, I am Microsoft certified 2008 and 2016 in SQL Server (2x MCTS, 2x MCTIP, MCSA, MCSE) and I am Microsoft Certified Trainer (MCT) also I am azure Certified (AZ-900, AZ-103) also I was awarded by Microsoft Azure Heroes 3 times as (Azure Content hero, Azure Community hero and Azure Mentor) For more information check my page https://mostafaelmasry.com/about-me/ View all posts by Mustafa EL-Masry