Improving Slow Query Performance: When Runtime Matters

As SQL users, we usually focus on writing queries that return correct results. However, there are more things to consider when you’re writing a query; one of them is query performance. In this article, we’ll look at some examples where query response time is critical. Scene One: 911 Call Center Let’s suppose we’re at a 911 call center, when the phone rings. One of the operators answers the call; a witness reports that a man has been shot. After the

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Data Analyst to Data Scientist: A New Skill Set for a New Future

Will robots replace humans in the near future? As machine learning and artificial intelligence continue to grow in popularity, this question becomes all the more relevant. Which jobs will become extinct, and what will society looks like in the future? If you’re a data analyst whose worried about their job security, don’t worry—there’s still hope for you! In this article, we’ll take a look at the skills a data analyst can acquire to become a data scientist and rise above

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Converting Subqueries to Joins

Not all queries are alike, especially in terms of performance. In this article, we’ll look at how you can convert SQL subqueries to joins for improved efficiency. When should I use SQL subqueries? Great question! Unfortunately, there’s no concrete answer. SQL beginners tend to overuse subqueries. Typically, once they find that SQL construction works in one situation, they try to apply that same approach to other situations. It’s only natural. However, in some cases a subquery can be replaced with

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Must-Know SQL Terms for Beginners and Pros

Working with databases can seem daunting to a non-technical person. Right away, you’re bombarded with new terms that make your head spin. Database, database instance, table, SQL and others are some of the basic terms that you need to understand just to have a normal conversation with your technical colleagues. In this article, we’ll explore some basic database terminology you need to know to succeed. Imagine you’re attending a meeting with the development staff and suddenly feel as if you’re

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Correlated Subqueries in 5 Minutes

If you’re familiar with the famous Russian nesting doll, then SQL subqueries should be a peace of cake to understand—subqueries are just queries nested within queries. An SQL subquery is often called an “inner” query; the main query is usually called the “outer” query. This article covers everything you need to know about correlated subqueries. What Exactly is a Correlated Subquery? A correlated SQL subquery is just a subquery that is executed many times—once for each record (row) returned by

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