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New Monthly SQL Practice for August 2021!
by LearnSQL.com Team
1 Aug 2021
Do you have basic skills in SQL? Do you know how to write SQL queries? If the answer is yes, you can test your knowledge by solving business problems with our SQL Practice, available every month on LearnSQL.com. The August SQL Practice is at the basic level. You will check your SQL skills with data about a travel agency. The company organizes trips through different cities in the state of Illinois in the US, connecting its clients to many attractions.
New to Data Engineering? Don't Make These Mistakes
by Himanshu Kathuria
30 Jul 2021
It's best to learn from the mistakes of others. This advice also works for data engineering. In this article, you'll find tips to help you advance your career and avoid common data engineering mistakes. The data revolution has produced tremendous opportunities and created various high-paying jobs related to the collection, maintenance, and manipulation of data. Data engineering is one of the most lucrative and interesting jobs of this family.
SaaS KPI Metrics, Part 1: Using SQL to Calculate Customer Lifetime Value (LTV) and Related Metrics
by Michal Stín
29 Jul 2021
Working with data is an essential skill for marketers in today's data-driven world. As a marketer myself, I decided to create a series of articles about calculating key performance indicator (KPI) metrics for SaaS (Software as a Service) companies. We’ll start by calculating customer lifetime value (LTV) using SQL. Data is one of today’s most valuable resources. If you work in a SaaS company, you are flooded with a huge amount of data every day.
An Overview of SQL Text Functions
by Zahin Rahman
28 Jul 2021
In this article, we will discuss the ins and outs of the most common SQL text functions, which make it possible for you to find and work on string values. Before we dive into text functions, let’s quickly recap what an SQL function is. Simply put, a function is a predefined built-in piece of code that you can use in your SQL query. For example, the functions SUM(), AVG(), and COUNT() are applied to numerical variables to calculate the sum, average, and number of records respectively.
How Will a SQL Course Improve the New Employee Onboarding Process?
by Jakub Romanowski
27 Jul 2021
Are you looking for something to improve the onboarding process of new employees at your company? If they will be working with databases and SQL, and if you need resources for them to learn quickly, choose interactive SQL online courses. You’ve just hired some new employees. Great! After a long recruitment process, you have finally managed to find people who can do the job and meet your expectations. You may have even used our advice on why it makes sense to Practice SQL Before Interviewing a Potential Employee.
SQL SUM() Function Explained with 5 Practical Examples
by Dorota Wdzięczna
23 Jul 2021
Aggregate functions are an important part of SQL knowledge – and there’s no better place to start learning them than with the SUM() function. In this article, you can expand or refresh your SQL with 5 practical examples of SUM(). SQL allows us to do more than select values or expressions from tables. Most operations on relational databases use aggregate functions like SUM() to do computations on data.
What Is the Difference Between WHERE and ON in SQL JOINs?
by Kateryna Koidan
22 Jul 2021
When you join tables in SQL, you may have conditions in an ON clause and in a WHERE clause. Many get confused by the difference between them. In this article, we will discuss this topic by first reminding you the purpose of the ON and WHERE clauses then by demonstrating with examples which types of conditions should be in each of these clauses. Both the ON clause and the WHERE clause can specify conditions.
How SQL Can Help You Democratize Data in Your Company
by András Novoszáth
21 Jul 2021
Are you drowning in an ocean of data but lack the staff to find the treasures in it? Do bottlenecks clog your data and reporting processes? Have you heard about data democratization and wondered what all the fuss is about? In this article, we answer your questions! If you are a part of an organization that works with data, limited access is one of your biggest bottlenecks. It impedes data-related processes and prevents you from generating insights about your business.
How to Keep Unmatched Rows When You Join two Tables in SQL
by Tihomir Babic
20 Jul 2021
Learn how to use JOIN to keep both matched and unmatched rows when you join two tables. Joining two or more tables is a skill you need a lot if you’re working with databases. And if you do it often, you’ve probably noticed not all data from one table corresponds to data from another table all the time. Sometimes, you need only the data that have a match in both tables.
Top 10 SQL Window Functions Interview Questions
by Ignacio L. Bisso
16 Jul 2021
Many interesting job positions require SQL skills – and that includes window functions, which are not commonly taught in online courses. In this article, I will cover the top window function questions for every experience level. If you’re going for a job interview for an advanced SQL position or for intermediate to advanced data analyst positions, you’ll probably be asked about your knowledge of SQL window functions. Don’t panic! Although these functions aren’t commonly covered in online courses, we’ve got the answers right here.