How SQL Server compiles, optimizes, and executes individual queries.
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You posted SQL Server questions and upvoted the ones you'd like to see at https://pollgab.com/room/brento, and before the Cabo Clasico finals start for the day, I sat by the pool to talk through 'em:
https://www.youtube.com/watch?v=--nU3K47Eyc
In a programming language like C# or Java, you tell the computer what to do, in order. Get the customers from California, then get their invoices, then sum the total. SQL, on the other hand, is a declarative language where you declare the shape of your result set: Get the total sales from Californian customers.…
When you see "index seek" on an execution plan, that doesn't mean SQL Server is jumping to exactly the row you're looking for. It only means that SQL Server is seeking on the first column of the index.
This is especially misleading on indexes where the first column isn't very selective.
I'm back in the US at my home studio in San Diego, so I did a live Office Hours session. Post your questions at https://pollgab.com/room/brento and upvote the ones you'd like to see me cover.
https://www.youtube.com/watch?v=i-W247nIBM4
Ah, sunset - time to kick back on the balcony, watch the ocean, and discuss SQL Server. You post questions at https://pollgab.com/room/brento/, upvote the ones you'd like to see me answer, and I discuss 'em:
https://www.youtube.com/watch?v=Vze_ClkDnhE
Ask me questions at https://pollgab.com/room/brento and upvote the ones you'd like to see covered. I can pretty well guarantee that your favorite question this time is going to be the last one I answered.
https://www.youtube.com/watch?v=grzauq0qiV8
Got SQL Server questions? Post 'em at https://pollgab.com/room/brento and upvote the questions you'd like to see me discuss.
https://www.youtube.com/watch?v=hmmaAwf4r4k
Got questions about SQL Server? Post them at https://pollgab.com/room/brento and upvote the ones you'd like to see me cover. This episode was the first live one I shot in my home studio in Cabo:
https://www.youtube.com/watch?v=BfQqQW1PCoM
You posted and voted on questions at https://pollgab.com/room/brento and I answer 'em on the beach. It's not your eyes: the camera's hunting for focus a lot in this video.
https://www.youtube.com/watch?v=nSfJmaY5sL8
You ask questions at https://pollgab.com/room/brento and I answer 'em from the beach in Cabo San Lucas:
https://www.youtube.com/watch?v=EQe6IWeTCTo
I watched the sun rise from my balcony in Cabo this morning and answer your questions from https://pollgab.com/room/brento.
https://www.youtube.com/watch?v=tNAyaTqKIpo
The short answer is that if your query orders columns by a mix of ascending and descending order, back to back, then the index usually needs to match that same alternating order. Now, for the long answer. When you create indexes, you can either create them in ascending order - which is the default: [crayon-6a73d87a02570791880755/] Or…
Let's pick up right where we left off yesterday. I've got more time and champagne, so let's keep going through your top-voted questions from PollGab.com/room/brento.
https://www.youtube.com/watch?v=raWyoVlW0lc
Let's watch the sun rise at Land's End and cover your top-voted questions from https://pollgab.com/room/brento/.
https://www.youtube.com/watch?v=rtriOfpu_SU
I went through your highest-voted questions from Pollgab and talked through 'em, and strangely, there was a bit of a 2008R2 theme!
https://youtu.be/3-B5L3Komq4
Not all of your questions need detailed answers. In this speed round, I race through 18 answers in 11 minutes:
https://www.youtube.com/watch?v=VaujdF1wp8w
Picking up right where we left off yesterday, we continue down through the not-so-highly-upvoted questions from https://pollgab.com/room/brento.
https://www.youtube.com/watch?v=saIwheS6_Mg
I hang out on my balcony in San Diego with a gin & tonic and a bunch of your highly upvoted questions from https://pollgab.com/room/brento.
https://youtu.be/kAzUupChX_Y
In my free How to Think Like the Engine class, we start out by measuring query performance using logical reads. That's the number of 8KB data pages that SQL Server has to read in order to find your query's results. That's the measure I use the most because generally speaking, the less data your server has to read, the faster your query will finish.
I'm up bright and early in Malibu, so let's talk through your highly upvoted questions from https://pollgab.com/room/brento.
https://www.youtube.com/watch?v=VwKeu4WAPuI
