Programmers commonly have many questions about R, a popular programming language in data science and analysis. R is used all over the world by professionals in the fields of data science, data visualization, data mining, and statistical analysis. But what exactly is R? Where did it come from? And why is it being used specifically by data science professionals? This article attempts to answer all these questions, including the most important of them all: Should you be learning R as well?
Why is June 21 the official start of summer? Let’s see how SQL can help us answer this question. The Summer Solstice Officially, June 21 is recognized as the summer solstice, the longest day of the entire year in terms of daylight. Why? Because on this day, the sun rises early and sets quite late. People in the Northern Hemisphere celebrate the summer solstice with feasts, bonfires, picnics, and traditional dances and songs.
In my previous articles, I explained how you can check for associations between two continuous and two discrete variables. This time, we’ll check for linear dependencies between continuous and discrete variables. You can do this by measuring the variance between the means of the continuous variable and different groups of the discrete variable. The null hypothesis here is that all variances between the means are a result of the variance within each group.
Have you ever wondered how you can deal with an overwhelming amount of data? How do you use it? How do you understand what it’s saying? And last but not least, how do you present your data to the world such that everyone understands your point? In this article, we’ll explore these questions to understand the importance of data visualization. Where are the data? When I want someone to understand my perspective, I try to visualize it precisely so I can communicate my thoughts.
Going from zero to one can be daunting in any endeavor. The same is true for learning new programming languages, even simple ones like SQL. In this article, we’ll take a look at some key insights that will help you understand the nuances of SQL queries. If you’ve never used SQL, you’re in the right place. When learning anything new, you’ll find that there are always some key insights or tips that can help you on your way.
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.
Data science professionals frequently coordinate their workloads, host meetings to discuss and share ideas, and collaborate to solve problems. But all it takes for things to fall apart is a lack of clear communication. Data Science is a team sport that involves a variety of professionals working together to solve technological problems. However, you need good communication for your team to run like a well-oiled machine. You may be thinking that poor communication isn’t that big of a deal.
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 these pesky robots 🙂
Unlock the potential of data! With this course, you’ll learn about data analytics, data science, statistical analysis, and functions in the R programming language. This course is perfect for people who have no prior knowledge of computer science or R programming. With Introduction to R, you’ll learn to work in the R programming language as you enter the promising world of data science. Why R is so famous According to the TIOBE programming community index, which ranks the popularity of all programming languages, R is one of the hottest programming languages of 2018.
There are many perceptions of IT, one of the fastest growing industries in the world. For a non-technical person, IT is usually associated with high salaries, numerous job offers, and elite clubs. But IT is more than just people earning big bucks for writing code. The most valuable part of the IT industry is its community. The first steps are the hardest As a complete IT newbie, I had lots of doubts and fears about entering the IT industry.
As an ambitious database administrator, you want to get ahead of the crowd and expand your knowledge. The best way to do that is to get certified in the technology you’re working with. This article and infographic will guide you through the most popular database administrator certifications on the market today. If you’re here, you’re passionate about working with databases, like many other IT professionals. Being a database administrator (DBA) will open up an IT field of pure engineering, with little consideration of the business side of your organization.
Are you the type of database administrator who organizes files by folder? Do you have a folder full of sorted folders? If so, then scrum is the right methodology for you. A database administrator (DBA) is an essential member of any IT team. DBAs create, maintain, and secure an organization’s database, in addition to overseeing user rights assignment, backups, querying, and database tuning. You need specialized training and technical expertise to manage the specific RDBMS setup used by your organization (to understand what an RDBMS is, read on), along with a quirk for analytical thinking.
Within organizations, Scrum promotes efficient time and process management along with better team building and leadership. In order to implement Scrum, you’ll need to follow a few simple rules. Introducing Scrum Today, we have the power to collect precise data both quickly and in vast quantities. In fact, 90% of the data available today was collected in the last two years alone. The rise of big data has greatly increased demand for data scientists, but the profession is one where few candidates possess the right skills.
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.
Brush up on your data science and SQL skills with Vertabelo Academy’s interactive courses. Why Vertabelo Academy? You get instant access to lessonsthat teach various concepts of SQL, data science, and programming in R (soon also in Python!). Our courses are appropriate for people who have no prior knowledge of computer science or programming. The only requirement is a web browser. No need to install databases, download example tables, or spend time inventing exercises for yourself.
Here’s a reality check: Big Data has hit us like a speeding truck on the highway of business intelligence. In today’s digital age, we’re generating data about ourselves that were once considered private, and we’re doing it willingly! From what we eat and wear to where we are at all times, nearly everything is now public knowledge. The data generated is a potential diamond mine for everyone in business, from one-person companies to Fortune 500 A-Listers alike, all thanks to the Internet.
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 listening to white noise.
Applying for an SQL-related position? You’ll likely have to pass an interview process. But you’ll be much better prepared for the interview if you know what to expect. This article sheds some light on the recruiter’s perspective to better prepare you for your interview. SQL Knowledge and Skills There are different SQL skills that an interview can test. These include: Skills related to any specific SQL database engine (like PostgreSQL, MySQL, or Oracle).
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 the outer (main) query.
If you’re looking to retrieve any kind of information from a database, you need to speak its language. But querying databases is an art—and it demands practice. We spend a lot of time not only developing new courses but also speaking with our users and learning what they have to say about online learning. This is how we came up with the idea of creating an SQL practice set.
Curious about becoming a database analyst? Maybe you’ve taken some database courses at university and they really struck a chord. Or maybe you learned online. Now you’re thinking about making a career out of working with databases. Where would you start? What should you expect at each phase of your professional development? In this post, we’ll explore the challenging and exciting world of databases analysis. We’ll go from the very beginning of a career to the apex of professional success.
Learn how to extract data from strings in PostgreSQL using the split_part function. Quite often, we’d like to extract parts of a string when working with text values. A common example is when we have a full name and need to retrieve only the last name. In this article, we’ll examine split_part, a PostgreSQL string-related function that can be used to extract a substring. Why Use String Functions in Your Database?
Data science is hot right now. If you want to learn more about it, where should you go? Online, of course! Check out our favorite data science sites. Whether you’re a beginner or a pro, these are sites you should know. Not so long ago, if you wanted information on a topic like data science, you had to look for it – either at your local library or at a university.
In this article, we’ll take a look at guidelines you should follow to create compelling visuals. Our goal is to learn how to effectively convey information through graphics. Have you ever looked at raw data—spreadsheets of stray numbers—and struggled to make sense of it? We’ve all been there, but it’s no surprise—because the human brain processes visualizations and images 10,000 times faster than raw data. In fact, 80% of the information we absorb comes from visuals, and the remaining 20% is text.
Excel allows business professionals to unlock the potential of their data – to a point. But when it comes to storing and manipulating large amounts of data, Excel can cause some problems. Excel has many good points. It’s often used by specialists to work with data related to their particular field. But it can come with problems, such as sluggish performance and difficult team collaboration. Even worse, Excel is vulnerable to the most dreaded problem of all: the accidental deletion of important data.
In this article, we’ll take a look at some of god-awful pie charts and hopefully learn a thing or two about good data visualization. March 14th is also known as PI Day. Mathematicians rejoice! π is a constant — the ratio of a circle’s circumference to its diameter — and it’s used in many different formulas. Baking and eating pies is super popular on this day — ’cause, you know, people just love their homophones.
Our world is bursting with data—the new digital age has dynamically inflated the volumes of data collected by businesses worldwide. By 2020, about 1.7 megabytes of new information will be created every second for every person on the planet. According to Forbes, The White House has already invested more than $200 million in big data projects. Can you imagine that? Seriously! Yet all the data that’s being generated by people, machines, online devices, and other sources doesn’t provide decision-makers with any valuable insights by itself.
We asked our users why they decided to learn SQL. This is what we’ve learned. At Vertabelo Academy, we help people with no computer science backgroundto understand the core concepts of databasesand data science. For example, we teach users how to extract the most important data from a database to build simple reportsand how to understand key statistical metrics in data analysis. We love to provide easy-to-understand examples that thoroughly depict complex technical concepts.
Learning to think in SQL will help you understand what SQL queries do, how to create and change them, and how to create reports from the data you obtain. One of the greatest skills you can have in SQL programming is this the ability to change an existing SQL query so you get the results you need. When you are first starting out, you likely will not create SQL queries from scratch but rather reuse what others have written.
We recently published a story from a Vertabelo Academy user who found her love thanks to SQL. On a similar note, I asked my colleagues to bring back old memories of writing their very first scripts. And yes, love is involved. Here at Vertabelo Academy, we’ve got some real OG programmers and data scientists making great content. They fell in love with data way before it was cool—and easy. So today, we’re jumping back in time to see what it was like to learn SQL before the Internet and Vertabelo Academy courses existed.
In today’s data-driven world, a good visualization goes a long way in helping people make sense of numbers. Every day at the office, we’re working hard to create programming and data science content that is accessible to everyone. We aim to produce content that is easy to understand, primarily for people with no IT background. And you know what? Ironically, this stuff ain’t easy even if you’re an IT specialist!
They say that if you do what you love, you’ll never work a day in your life. At Vertabelo Academy, we strongly believe in this adage. We’re creating courses because it’s what we enjoy doing. We’re passionate about SQL and data science, and we want to deliver the best content possible in these domains. To that end, we provide our users with practical modules because learning by doing is the best way to master a new skill.
Just in time for Valentine’s Day, we discover which of Gary and Sara’s friends are in love – and how to use the SQL JOIN statement to work with data in multiple tables! Did you know SQL is a matchmaker? That’s right; it loves to make data couples by linking information from two (or more!) tables using the JOIN statement. However, many SQL rookies run into problems using JOIN. So let’s go to a party and learn how to use JOIN the right way!
Unwanted characters in text data can be a bit of a pain, but there’s an easy way to fix them! Sometimes, we’ll find extra characters inside our string data because our SQL queries didn’t work as expected. Moreover, these extra characters may sometimes be invisible, which really complicates things. In this article, we’ll examine some string-related SQL functions that can handle unwanted characters—visible or not! The Importance of Standardizing Strings in Your Database When we work with data populated or loaded as free text, the data quality is often quite poor.
Misspelled names, typos, and text data quality issues in your database? Power up your queries! Use SQL string functions to address data quality issues related to capitalization. Sometimes, our SQL queries don’t work as expected because of data quality issues. In this article, we will examine some string-related SQL functions that can correct data quality issues related to capitalization. We’ll be using PostgreSQL in our examples, but similar functions are available in most database engines.
Show, don’t tell! Share data insights in stunning color and display with ggplot2, a wonderful R package for visualizing data. Ggplot2: Grammar of Graphics The end of qualitative data analysis should be clear—beautiful data visualizations. We are visual beings, after all, and a picture tells us far more than raw numbers! Among the many visualization tools, one in particular stands out : ggplot2—a free, open-source, and easy-to-use package that has become a favorite among many R programmers.
For this post, I’ve gathered 15 of the most interesting SQL articles published in 2017. If you’re an SQL beginner and are interested in learning more about databases and SQL queries, or if you’d just like to expand your knowledge of SQL, this article is perfect for you. Let’s dive right in! Top 3 Vertabelo Academy articles I’ll start off the list with three of the most popular Vertabelo Academy articles.
Mastering the basics for a smooth start to SQL Learning a new programing language can seem intimidating. Like any other language, a programming language has a large vocabulary that you need to master. In this article, we’ll look at some of the most important SQL functions that you need to know. SQL is a rich language with many useful functions for working with different data types. Once you practice with some of the most important SQL functions, you’ll gain enough confidence to move on to more advanced material.
Unfortunately, all good things must come to an end—this is your last query task for this season! We hope you’ve enjoyed the challenges so far. The good news, however, is that you got to practice your SQL skills. At this point, you’re only one step away from completing ourcrosswordand getting a Vertabelo Academy discount on a course of your choosing. Task #24: How much did Santa Claus pay for each toy he purchased from the musiccategory?
Wanna be part of this year’s Christmas success? Santa needs your help organizing his Christmas deliveries. For this occasion, we’ve prepared a special Christmas database. While working on tasks, you’ll help Santa Claus deliver gifts to children. For this upcoming Christmas, we’ve prepared a 24-Day SQL Advent challenge. From now until Christmas Eve, we’ll publish daily SQL tasks for you to complete. If you’ve completed or recently started our SQL Basics course, or if you already have basic SQL knowledge, then this event is perfect for you!
Task #23: Santa Claus ordered a gift for a particular child on December 12th, but that gift has not been delivered yet. Who is the child? Answer 23 for the crossword: The child’s name. Challenge Accepted? Use the SQL Advent Challenge sandbox to solve tasks and practice writing all kinds of SQL queries.
Task #22: Find the name of the toy that most children asked for in their letters. Select the toy name and the number of requests for this toy. Answer 22 for the crossword: The toy name. Challenge Accepted? Use the SQL Advent Challenge sandbox to solve tasks and practice writing all kinds of SQL queries.
You can use SQL to manipulate all kinds of data, from huge analytical queries to brief single-purpose statements. But you can also use SQL just for fun, without any business requirements stifling your creativity. So, get out your jolly hat and prepare to sing O Christmas Tree as we create some quirky art with plain old SQL. Today, we’re going to generate some holiday-themed ASCII art, just for fun. That’s right.
Task #21: Santa Claus wants to buy some surprises for children from Argentina who either didn’t ask him for any toys or simply didn’t send him any letters. Help Santa Claus find the names of these children. Sort the records by child name in ascending order. Answer 21 for the crossword: The name of the last child in the result set. Challenge Accepted? Use the SQL Advent Challenge sandbox to solve tasks and practice writing all kinds of SQL queries.
Task #20: Retrieve the name of the child who did not write a letter to Santa and whose country name is composed of two words. Answer 20 for the crossword: The child’s name. Challenge Accepted!? Use the SQL Advent Challenge sandbox to solve tasks and practice writing all kinds of SQL queries.
Task #19: In which store did Santa Claus spend the most on gifts? Answer 19 for the crossword: The second word in the store name. Challenge Accepted? Use the SQL Advent Challenge sandbox to solve tasks and practice writing all kinds of SQL queries.
Task #18: How many letters were written by children from countries other than those in which there was at least one naughty child? Answer 18 for the crossword: The number returned by the query, with the digits reversed. Challenge Accepted? Use the SQL Advent Challenge sandbox to solve tasks and practice writing all kinds of SQL queries.
Task #17: Which children were naughty this year, and what countries are they from? Sort the records by country name in descending order and by child name in ascending order. Answer 17 for the crossword: The name of the last child in the result set. Challenge Accepted? Use the SQL Advent Challenge sandbox to solve tasks and practice writing all kinds of SQL queries.
Task #16: Retrieve the largest number of toys that children asked for on a particular day during the period from December 6, 2017 through December 16, 2017. Answer 16 for the crossword: The number returned by your query. Challenge Accepted? Use the SQL Advent Challenge sandbox to solve tasks and practice writing all kinds of SQL queries.
In my previous article, we looked at how you can calculate linear dependencies between two continuous variables with covariance and correlation. Both methods use the means of the two variables in their calculations. However, mean values and other population moments make no sense for categorical (nominal) variables. For instance, if you denote “Clerical” as 1 and “Professional” as 2 for an occupation variable, what does the average of 1.5 signify?