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Curated SQL Posts

A Crash Course on Synapse Studio

Published 2022-12-09 by Kevin Feasel

Kevin Chant wants six minutes of your time:

In this post I want to do a six-minute crash course about Synapse Studio. I wanted to do this follow-up post for a couple of reasons.

First reason is because a while ago somebody who was fairly new to Azure Data Engineering Services mentioned that they thought a lot of my posts were for advanced users. So, I showed them a previous post which was a five-minute crash course about Synapse Studio.

Whilst showing them that post I realized that some of the screenshots were out of date. With this in mind I thought I would do an updated version of the crash course for Synapse Studio. Which also allows me to highlight where to find some features.

Start your timers and get reading.

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The Benefits of Stacking Pull Requests

Published 2022-12-08 by Kevin Feasel

Vivian Qu explains why stacking pull requests can make sense:

Becoming proficient in version control and change management is a necessary part of any software engineer’s job. However, I think that basic proficiency alone is not sufficient to be truly effective when working on complex production-ready software with a team of engineers. Stacking pull requests (PRs) is a key skill that should be learned early in a junior engineer’s career.

Stacking PRs is an advanced git technique that allows an engineer to break down one large change into a series of dependent changes that can be turned into smaller pull requests and reviewed separately.

Read on to learn more. It’s a skill I definitely don’t have, so time to add that to my to-learn list.

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Installing ML Services on SQL Server 2022

Published 2022-12-08 by Kevin Feasel

Tomaz Kastrun notices a change to the SQL Server installer:

Machine Learning Services and language extensions is available under Database Engine Services, and if you want to use any of these languages, check this feature. During the installation process, the R, Python or Java will not be installed (nor asked for permissions), but you will install your own runtime after the installation. This will bring you more convenience with the installation of different R/Python/Java runtimes.

Read on to see how you can install and work with languages like R, Python, and Java in SQL Server 2022.

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The Purpose of Data Encryption

Published 2022-12-08 by Kevin Feasel

Matthew McGiffen thinks through the benefits of encryption:

On the face of it, this is a very obvious question with a very obvious answer. We want to prevent data from falling into the wrong hands. In practice, it gets a little more complicated.

Exactly what types of attacks do you wish to be protected against? It’s good if we make sure our data is encrypted where it is stored on the disk, but that doesn’t help us if an attacker gains direct access to write queries against the database. We might encrypt data held in columns, but does that still protect us if the unencrypted data is being passed back across the network to our application and an attacker is intercepting our network traffic?

I did a Ctrl-F for “compliance” and didn’t see anything. Nor for checking boxes to keep regulators off our backs. It seems Matthew is going for the good answers here.

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Solving Common CALCULATE Filter Argument Errors

Published 2022-12-08 by Kevin Feasel

Marco Russo and Alberto Ferrari catalog some errors:

The expression contains columns from multiple tables, but only columns from a single table can be used in a True/False expression that is used as a table filter expression.

This error is seen when the predicate includes column references from more than one table. For example, if we need a measure that returns the sales made to customers living in the same country as the store, we could try to write the following measure:

Read on for several examples and solid guidance on how to resolve these common issues.

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Roll Your Own Row-Level Security for the Serverless SQL Pool

Published 2022-12-08 by Kevin Feasel

Randheer Parmar wants row-level security:

Row Level Security is a very key requirement for most database or data lake applications. Most of the databases are having natively build row-level security but Synapse serverless SQL pool doesn’t support this inbuilt functionality. In this article, we will see how to implement it.

Row-level security has always seemed to me to be a great idea but not one I can implement because its performance cost is always too high.

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Distinct Counts in KQL

Published 2022-12-07 by Kevin Feasel

Robert Cain continues a series on KQL:

In an earlier post in this series, Fun With KQL – Count, you saw how to use the count operator to count the number of rows in a dataset.

Then we learned about another operator, distinct, in the post Fun With KQL – Distinct. This showed how to get a list of distinct values from a table.

While we could combine these, it would be logical to have a single command that returns a distinct count in one operation. As you may have guessed by the title of this post, such an operator exists: dcount.

Read on to see how you can use dcount in queries, including how you can perform speed versus accuracy trade-offs.

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InvalidAbfsRestOperationException in Synapse Managed VNet

Published 2022-12-07 by Kevin Feasel

Kamil Nowinski goes down a rabbit hole:

This happens on the customer’s Synapse workspace where we have a public network disabled, so only private endpoint and managed VNET are available. Additionally, you probably spotted, that it took over 3 minutes to actually get this message. Hence, as a next step, in order to minimize the potential causes I simplified the query to make sure I have access to the Storage, by listing the files:

Click through for a story of pain, followed by glorious resolution.

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