Maintainable T-SQL and patterns that avoid correctness and performance problems.
106 associated posts102 primary posts
Your queries won’t tune themselves. My 2027 Live Class Season Pass is $995 (normally $4,395), with live Fundamentals and Mastering classes plus recordings. Register by October 31 to join Fundamentals Week, November 2–6. See the pass.
For this month's T-SQL Tuesday, I invited y'all to tell me how you know a query's gonna be bad when you open it.
Your queries won’t tune themselves. My 2027 Live Class Season Pass is $995 (normally $4,395), with live Fundamentals and Mastering classes plus recordings. Register by October 31 to join Fundamentals Week, November 2–6. See the pass.
I open it up and the first thing I see is a comment with a changelog showing a long list of dates and author initials.
Microsoft SQL Server Management Studio 22.7 added the ability to format your T-SQL queries by right-clicking and clicking Format SQL, or by hitting control-K, control-Q on your keyboard:
You're probably not going to like the default formatting out of the box because you're the kind of person who has strong, passionate feelings and likes to argue about them on the Internet. Good news! The configurations are really flexible. Go into Tools, Options, SQL Formatter:
Ever just need a quick visualization of some numbers to get a rough idea of the trend, like this:
Option 1: ask Copilot to write the query for you.
Copilot in SSMS has two parts. Usually people focus on the pop-out Copilot chat window, and that's useful for sure, but honestly I think you're going to get way more mileage out of the code completions feature, right away, because it blends in with your existing workflows. Let's say that I'm working with the Stack…
I know a lot of y'all lag behind on upgrading SSMS, but v22.3 just introduced something that you need to be aware of. It's going to impact any of your users who DO upgrade their SSMS, or who use Github Copilot. There's something that you can do in order to improve Copilot's code quality and make it match your preferred coding standards.
This seems like the appropriate first BrentOzar.com blog post in the year 2026, eh?
In the PollGab question queue for Office Hours, MyRobotOverlordAsks asked a question that merited a full blog post answer:
Your queries won’t tune themselves. My 2027 Live Class Season Pass is $995 (normally $4,395), with live Fundamentals and Mastering classes plus recordings. Register by October 31 to join Fundamentals Week, November 2–6. See the pass.
You're building a new table or adding a column, and you wanna know which datatype to use: VARCHAR or NVARCHAR?
When I'm tuning queries, the normal answer is to make the query perform better - either via changing the T-SQL, adding hints, or adding indexes so that the data's better prepared for the query.
However, sometimes when I'm looking at the output of sp_BlitzCache, I scroll across to the Average Rows column and double-check that the query's actually returning a reasonable number of rows out in the wild.
When I see horrific code, stuff that would take a lot of manual labor to fix, I like to lob it over to an LLM like ChatGPT just to see how it does.
For example, on a call with a client, I opened up one of their slowest pieces of code to find that it was running a cursor, processing data row by row rather than working in sets. To simulate it, I've written up a few stored procedures against the Stack Overflow database:
Most of the time, I love Entity Framework, and ORMs in general. These tools make it easier for companies to ship applications. Are the apps perfect? Of course not - but they're good enough to get to market, bring in revenue to pay salaries, and move a company forwards.
However, just like any tool, if you don't know how to use it, you're gonna get hurt.
My Asian vacation continues in Kyoto, the City of a Thousand Temples. They're not playing around - the town is chock full of gorgeous historic temples, and it was tough to pick a scene for today's Office Hours. Let's go through your top-voted questions from https://pollgab.com/room/brento:
https://youtu.be/6zpEXYeDH1Q
SQL Server Management Studio v21 added native Git support, making it easier to use source control natively inside SSMS. This feature is for developers who are already used to working with Github to manage specific object changes as they work, and who are already accustomed to Git terminologies like branches, commits, pushes, and pulls. This…
So you're writing T-SQL code and you've decided that you want to send emails to customers, employees, or the general public. Perhaps you need to send order updates or low stock notifications.
Stop right there. You don't really wanna do that with SQL Server. Let's talk about why.
I'm not talking just about Microsoft SQL Server specifically here, nor T-SQL. Let's zoom out a little and think bigger picture for a second: is the SQL language itself a problem?
Sometimes when I talk to client developers, they gripe about the antiquated language.
In last week's post, I gave you a trigger that populated a history table with all changes to the Users.AboutMe column. It was your job to write a T-SQL query that turned these Users_Changes audit table rows:
Into the full before & after data for each change, like the earlier query from the blog post:
For this month's T-SQL Tuesday, Pinal Dave asked us if AI has helped us with our SQL Server jobs. For me, there's been one instant, clear win: code reviews. I usually keep a browser tab open with ChatGPT 4, and I paste this in as a starting point: You are an experienced, diligent database developer…
Your Query Exercise was to find denormalization accuracy problems: checking the accuracy of a reporting column, Posts.CommentCount. There were two parts: finding the top 100 most problematic Posts with the biggest variances, and thinking about a long term solution to keep the CommentCount accuracy as high as practical. Question 1: Finding the Problematic Posts Your…
For 2024, I'm trying something new: weekly homework challenges! For this week's query challenge, we're going to do some data validation. Pop open the Stack Overflow database and check out the CommentCount column on the Posts table: In theory, that's a fast way to check how many Comments a particular Post has, without querying the…
The first time I saw FOR XML PATH being used to generate a comma-delimited list, I think I stared at it, shook my head to clear the cobwebs, stared at it some more, and then closed the code editor thinking it was complete witchcraft.
And that same thing probably happened the next several times, too.
