Query Exercise: Find the Best Time for Maintenance

If we’ve gotta take the database down for maintenance – perhaps a version upgrade, perhaps upgrading our own code, maybe scaling up the hardware – when’s the best time to do it?

Deploying Azure SQL Database Using an ARM Template

Provisioning infrastructure in a timely and reliable manner is essential for agile development. One well-liked method that lets you use code to automate resource management and provisioning is infrastructure as code (IaC). Azure Resource Manager templates are one IaC solution for Azure (ARM templates).

Gracefully Handle Errors using TRY CATCH Logic in SQL Server Stored Procedures

Learn how to capture errors in SQL Server stored procedures and gracefully handle errors using Try Catch coding in your stored procedures.

SQL WAITFOR Command to Delay SQL Code Execution

One of the most rarely used commands in SQL is the WAITFOR command. It is one option to invoke a delay in program execution in absentia. Because it is sparsely used, how and where it can be applied when needed is often forgotten. For example, we could use this to mimic a user response or input or perhaps to collect data at certain intervals during the day.

What is the rounded result?

Two-Dimensional Interval Packing Challenge

Packing intervals is a classic SQL task that involves packing groups of intersecting intervals to their respective continuous intervals. In mathematics, an interval is the subset of all values of a given type, e.g., integer numbers, between some low value and some high value.

Eager Aggregation in SQL queries

Aggregation is a widely used way to summarize the content of a database. It is usually expressed with GROUP BY clause or just using aggregate functions (like COUNT or SUM). When the database engine executes a query with aggregations, it produces individual rows need to compute the required output and then performs the aggregation as (almost) last step. We discuss in this article how to re-write a query manually so that the order of operations will be different and when it can be beneficial.

Counting more efficiently

Nearly a decade ago, I wrote a post called “Bad habits : Counting rows the hard way.” In that post, I talked about how we can use SQL Server’s metadata to instantly retrieve the row count for a table.

Dijkstra's Algorithm

Introduction This article celebrates a classic algorithm [1] of Dijkstra (1930 – 2002) which finds a path of minimal cost between any pair of nodes in an undirected graph. His procedure is widely recognized as a fundamental tool for examining communication and transportation networks (eg. Google Maps) and is surprisingly simple. By his own admission, […]

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