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Articles
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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.
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11 Feb 2021
Kateryna Koidan
Enumerate and Explain All the Basic Elements of an SQL Query
“What are the basic elements of an SQL query?” is a popular SQL job interview question. In this article, we review the basic syntax of an SQL query. An SQL query, which requests information from a relational database, consists of several elements. These allow you to select specific columns from specific tables and to filter and sort this information if necessary. In this article, I’ll briefly review these elements by explaining what each element does and how to use it.
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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.
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9 Feb 2021
Kateryna Koidan
What Does ORDER BY Do?
When analyzing data, it often helps to have rows ordered in a specific way. In this article, I’ll use multiple examples to show how SQL ORDER BY sorts data according to one or more columns in ascending or descending order. Introduction to ORDER BY By default, the order of rows in the output of an SQL query is arbitrary. If you want to sort the output in a particular order, you’ll need to use the ORDER BY keyword.
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5 Feb 2021
Jakub Romanowski
How to Import CSVs to PostgreSQL Using PgAdmin
Do you work with data and use CSV files? Here is a practical guide on how to import such files into a PostgreSQL database using pgAdmin, one of the best PostgreSQL editors on the market. Let's get right into importing CSVs into a Postgres database. We’ll start by explaining what a CSV file is, then we’ll introduce you to pgAdmin and show you how to do the import process. Don’t worry – it’s easy!
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4 Feb 2021
Martyna Sławińska
What Is a Unique Constraint in SQL?
To ensure the uniqueness of data in a database, we use the SQL UNIQUE constraint. In this article, we’ll discuss how, when, and why to implement it. The idea of a unique constraint is not unique to SQL; it’s a familiar concept in real life, although we probably call it something else! For example, think of ID numbers. There can be only one social security number (SSN) per person and each one must be unique.
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3 Feb 2021
Rebecca McKeown
How Much SQL Do I Need to Know?
Learning a new skill or starting a new profession can be a real challenge, especially when you’re unsure of how much you really need to know before taking the plunge. Imposter syndrome is also a real thing – how could you possibly catch up with all those SQL ‘experts’ who seem like they’ve been doing this since they were in diapers? The good news is you can learn SQL quickly and easily, and you don’t need to know nearly as much as you think you do.
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2 Feb 2021
LearnSQL.com Team
SQL Course of the Month – SQL JOINs
If you want to really learn SQL, you can’t skip SQL JOINs. They are some of the most fundamental and commonly used features of the SQL language. That’s why SQL JOINs is our February SQL Course of the Month. What makes SQL JOINs so important? I asked Agnieszka Kozubek-Krycuń, Vertabelo's Chief Content Officer, about it. Here's what she said. Is it true that SQL JOINs are one of the foundations of SQL?
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1 Feb 2021
LearnSQL.com Team
New Monthly Challenge for February 2021!
Are you ready to solve business problems using SQL in 2021 with a new Challenge on LearnSQL.com? The February Challenge is at a basic level. You will test your SQL skills with data about a rental car company in the U.S. If it is the first time you’ve come across our Monthly Challenges, LearnSQL.com offers one free SQL Challenge each month: at the basic level in the even months and at the advanced level in the odd months.
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29 Jan 2021
Ignacio L. Bisso
Data Types in SQL
Read this article and learn the ABC of SQL data types. Data types are used to define the type of data stored in a database. However, there are related concepts that a good SQL developer should know: data type conversion, what operations are possible between different data types, date arithmetic, etc. SQL also provides functions that manipulate values of different data types (i.e. functions for string data, date and time data, etc.
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