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SQL

Mixing Grouping and Window Functions

We revisited window functions last week for T-SQL Tuesday. As we’re in that area there’s another example I thought was worth exploring. Can we group data whilst applying window functions in the same query? The problem For our example we’ll use the same sample data as last week. This contains sales values broken down by period, also […]

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SQL

Removing the Shackles on Parallelism

Our SQL Server environments are home to many workloads. In these situations one size doesn’t always fit all when it comes to configuration. Let’s take an example. On one hand we want small, high performance, transactional processing during the day. Through the evening this could change to larger, batch processing tasks. I’ve seen the configuration […]

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SQL

Deeper into Concurrency Contention

We’ve recently looked at how single threaded concurrency was handled in SQL Server and followed up last time by diving into multithreaded concurrency. This time we’re going to go a bit further with the multithreading to look more into how the contention is handled when the number of cores available doesn’t line up with our workload. We’ll also […]

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SQL

Effectively Deploying Stored Procedure Changes

If writing code is the meat of our work then then packaging our stored procedures for deployment is the bread and butter to complete the sandwich. Deploying them is key so here we’ll be looking at options for how to effectively script those changes. The specific challenge we’re looking at here is how to change […]

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SQL

More Caring, More Sharing: Handling Datasets within Sessions

When building data solutions we’ll be handling sets of data which may need to be imported, transformed, aggregated or exported amongst other things. With more complex solutions can come a need to share this data between different areas of the process. Last week we looked at being able to share individual values within a session and […]

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SQL

Sharing is Caring: Exchanging Values within Sessions

When developing application code we may be familiar with exchanging data and objects through the application. This practice is much less common in SQL due to being transactional when we consider application / OLTP workloads. There are however some times when exchanging values between code in the same session which is what we’ll start to […]

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SQL

Utilising Bit Masks with Bitwise Operators

A few weeks back we looked at options for storing multiple boolean flag values in a table. One of the options we considered was the use of a Bit Mask where we packed multiple flags into a single field. When we have individual fields within a table, using and manipulating those is straightforward. However when we’ve got […]

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SQL

Designing Long Running Procedures for Maintainability

Whilst we have front-end code which requires faster response times, there are also times we build code with the purpose of running for extended periods of time. Examples of this could be maintenance routine, or custom built queuing mechanisms. The way in which we design longer running processes like this can be key when it […]

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SQL

Calculating String Lengths

We store a wide variety of data within our platforms, some of which will inevitably be string based. Along with that comes a need to perform manipulation of those strings. When slicing, combining, or manipulating strings one element which we need to consider is the length of the string. Here I wanted to have a […]

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SQL

Recursive Functions and Limitations

When writing functions within SQL Server we sometimes have need to repeat an action multiple times until a given condition is met – also known as Recursion. There are a couple of common ways which this can be implemented which also have their different limitations. A little about recursion Firstly, why do we need recursion? […]