21 May 2021 Tihomir Babic 8 Best SQL Window Function Articles Do you need a starting point for learning SQL window functions? Not sure which articles provide a solid foundation? We dove into the internet rabbit hole and found the eight best articles dealing with window and analytic functions. There are plenty of articles dealing with SQL window functions. Type those words into Google and you’ll find a huge number of articles returned. Reading articles is a good start if you want to learn something about window or analytic functions in SQL – provided, of course, that the articles you choose are trustworthy and up to date. Read more 19 May 2021 Tihomir Babic What Is Advanced SQL? Are you confused about advanced SQL skills? What are they? This article will explain what advanced SQL can mean, especially as we use it on LearnSQL.com. I’m sure you find the phrases ‘advanced SQL skills’ or ‘advanced SQL topics’ very often. You read one article about advanced SQL and you’re happy with how easy these advanced topics seem to be. Then you talk to someone and you see they consider everything you know as basic SQL knowledge. Read more 20 Apr 2021 Tihomir Babic Hierarchical Data and How to Query It in SQL How do you recognize hierarchical data, and how do you query it? Two common SQL questions are about to be answered. Querying hierarchical data is a rather common situation if you’re working with SQL and relational databases. Not that hierarchical data is something mystical and rare; on the contrary, it’s everywhere. So why is hierarchical data so challenging when it comes to relational databases? Mainly, the difficulties occur in translating hierarchical data to relational database principles. Read more 6 Apr 2021 Tihomir Babic How to Find the Next Non-NULL Value in SQL You need to find the next non-NULL value in a time series, but you don’t know how. Can you even do that in SQL? Yes, you can! This article will show you what to do. If you work with SQL, you will sooner or later confront NULL values. Having NULLs in a database is almost unavoidable. However, sometimes you want to avoid them in your reports. This is quite often true when you’re analyzing time series data; NULL values mean there’s no data available. Read more 12 Mar 2021 Tihomir Babic SQL JOIN Topics That Require Practice Are you interested in learning how to join tables in SQL? Where do you start? Many JOIN topics require practice. In this article, we’ll explore these topics by writing codes to solve real-life situations. Hopefully, you will learn which JOIN topics require attention. To make it easier for you, the topics are divided into beginner, intermediate, and advanced. Joining two or more tables in SQL lifts data analysis to another level. Read more 5 Mar 2021 Tihomir Babic How to Get Descendants of a Parent in SQL Want to learn how to handle family trees and find descendants of a parent? By reading this article, you’ll learn how to handle hierarchical data. Finding descendants from a parent is a common problem in SQL. If you imagine a family tree, the basic building block that forms the relationships within it is the parent-child relationship. The parent-child relationship is precisely what defines all hierarchical data. Another example of hierarchical data is the manager-employee relationship. Read more 12 Feb 2021 Tihomir Babic 6 Advanced SQL Queries for Analyzing Financial Data Are you an advanced SQL user who’s new to finance? Do you want to learn how to use your knowledge to analyze financial data? The article will give you some guidance. You probably know that SQL is a potent tool for analyzing all sorts of data. The bigger and more complex data, the more beneficial SQL becomes. In certain situations, financial data can be very complicated; producing a sophisticated analysis requires sophisticated tools. Read more 10 Feb 2021 Tihomir Babic Want to Learn Advanced PostgreSQL? Try This! Why and how should you learn advanced PostgreSQL? I’ll give you some tips that will help you achieve your goals. Keeping up with technology is hard; anyone who has foolishly tried to do so can confirm this (me, for example!). Most of the time, it just doesn't work. And to be brutally honest, keeping up with all the technologies all the time is pointless. You shouldn’t know everything about everything; it’s better to know as much as you need within the technology you use or want to use. Read more 1 Jan 2021 Tihomir Babic SQL JOIN Tips for Beginners If you’re a beginner and want to know how to start using SQL JOINs in your queries, you’ve come to the right place. Using the SQL JOIN clause is necessary if you want to query multiple tables. Sooner or later, you’ll have to use more than one table in a query. It’s the nature of relational databases in general – they consist of data that’s usually saved in multiple tables; in turn, these form a database. Read more 15 Dec 2020 Tihomir Babic How to Use CASE WHEN With SUM() in SQL This article will teach you what a CASE WHEN expression is in SQL and how to use it with a SUM() function and a GROUP BY statement. The examples are included to bolster your understanding. The best way to learn about CASE WHEN and how to use it with SUM() is our hands-on course Creating Basic SQL Reports. It contains over 90 interactive exercises that will teach you different techniques how to create complex reports in SQL. Read more «« « 1 2 3 … 6 7 8 9 » »»