Articles Cookbook
21 May 2024
Tihomir Babic

SQL Window Functions Guide

Every data analyst can benefit from knowing SQL window functions. They up your data analysis game and open doors to analyzing data on an entirely new level. This article is your starting point for the world of SQL window functions.   SQL window functions allow you to show all the data rows and their aggregate values at the same time. Sounds a bit like GROUP BY on steroids, doesn’t it?
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16 May 2024
Radu Gheorghiu

Integrating External Data Sources with SQL Databases

In today's world, data is the new currency and organizations are swimming in vast oceans of information from various sources. Trying to make sense of all this disparate data is a challenge; one of the most common ways to solve that challenge is by integrating external data sources with SQL. In this article, I'll guide you through strategies and techniques for seamlessly blending data from APIs, flat files, NoSQL databases, and other external sources into your SQL databases.
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14 May 2024
Gustavo du Mortier

11 SQL Common Table Expression Exercises

In this article, we offer you 11 practice exercises that put your knowledge of common table expressions (CTEs) into practice. Each CTE exercise is accompanied by a solution and a detailed explanation. As the saying goes, “A little progress each day adds up to big results”. And that is undoubtedly true for SQL proficiency. Just as you should regularly go to the gym to keep your muscles toned, you should do common table expressions exercises often to keep your querying skills toned for heavy data analysis work.
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13 May 2024
Agnieszka Kozubek-Krycuń

SQL FIRST_VALUE Function

Discover the power of the FIRST_VALUE function, a window function that returns the first value in an ordered partition of the result set. This function is useful for anyone doing data analysis in SQL. Window functions are a powerful category of functions that enable doing sophisticated data analysis in SQL. These functions operate over a "window" of rows related to the current row, allowing for preparing complex reports like running totals, moving averages, preparing rankings, and others.
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9 May 2024
Martyna Sławińska

SQL String Functions: A Complete Overview

A review of all core SQL string functions, including their definitions and examples. SQL string functions manipulate string (including text and alphanumeric) values. Also known as text functions in SQL, string functions take one or more string values as an argument and return a modified string value. Check out this interactive course on Standard SQL Functions if you want more hands-on practice than this article includes. It provides 211 exercises on numeric SQL functions, string or text functions, date and time functions, and aggregate functions.
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7 May 2024
Nicole Darnley

Data Visualization Using SQL: A Guide for Data Analysts

Start exploring data visualization using SQL with our practical guide. You’ll learn how to harness the powerful features of SQL to create effective visualizations that enhance your data analysis – and make it more understandable and impactful. SQL is a specialized programming language designed for managing and manipulating relational databases. It provides a standardized framework for querying, updating, and manipulating data. It is simple and yet offers a robust set of commands and functions to interact with data.
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2 May 2024
Maria Durkin

The Data Analysis Lifecycle: From Dataset to Presentation

In today's fast-paced decision-making climate, data is an invaluable resource. Raw data is like a rough diamond: it has great potential, but it must be processed to reveal its true brilliance. Achieving this brilliance is where the data analysis lifecycle comes in. The data analysis lifecycle maps out a structured journey of five steps: Collection Cleaning Analysis Interpretation Presentation Mastering the right tools for each step is key, and that's where SQL proves indispensable.
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1 May 2024
Jakub Romanowski

Course of the Month: 2023 Basic Monthly SQL Practice

Start enhancing your SQL skills this May with our free SQL course, 2023 Monthly SQL Practice Sets - Basic! Spring is a great time to learn something new or improve your current skills. This May, we’re offering a unique opportunity to boost your SQL knowledge through practical exercises drawn from real-world business scenarios. Available free for the entire month, our 2023 Monthly SQL Practice Sets - Basic course provides interactive challenges involving databases from different industries.
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30 Apr 2024
Jill Thornhill

The SQL MIN() Function

SQL has a variety of powerful aggregate tools, including the SQL MIN() function. This article is a quick reference guide to extracting and using minimum values in your queries. In today’s cutthroat business environment, it’s vital to be able to analyze your organization’s data effectively to make informed decisions. SQL’s aggregate functions let you carry out all kinds of statistical analysis on your data. This article is a reference guide to the SQL MIN() function, which extracts the smallest item from a column of data.
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29 Apr 2024
LearnSQL.com Team

10 Correlated Subquery Exercises with Solutions

Correlated subqueries are a powerful SQL feature essential for advanced data analysis. This article provides 10 practical exercises to help you master correlated subqueries. SQL is a fundamental skill for anyone working with data, whether as a data analyst, a SQL developer, a data engineer, or any other related profession. Mastering SQL involves more than just understanding the basics. It also requires learning advanced SQL features, such as subqueries.
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