This post updates a previous very popular post 50+ Data Science, Machine Learning Cheat Sheets by Bhavya Geethika. If we missed some popular cheat sheets, add them in the comments below.
- Python For Data Science Cheat Sheet Datacamp
- Spark Dataframe Cheat Sheet
- Pandas Python Dataframe Cheat Sheet
- Sql Cheat Sheet Datacamp
Cheatsheets on Python, R and Numpy, Scipy, Pandas
Data science is a multi-disciplinary field. Thus, there are thousands of packages and hundreds of programming functions out there in the data science world! An aspiring data enthusiast need not know all. A cheat sheet or reference card is a compilation of mostly used commands to help you learn that language’s syntax at a faster rate. Here are the most important ones that have been brainstormed and captured in a few compact pages.
Summarize Data Make New Columns Combine Data Sets df'w'.valuecounts Count number of rows with each unique value of variable len(df) # of rows in DataFrame. In this SQL Query cheat sheet you will learn. What You Will Learn: show Create Database. MySQL SELECT statement command. MySQL WHERE clause commands. MySQL Command INSERT INTO Table. MySQL DELETE command. MySQL Update Command. This part of the Hadoop tutorial includes the Hive Cheat Sheet. In this part, you will learn various aspects of Hive that are possibly asked in interviews. This Apache Hive cheat sheet will guide you to the basics of Hive which will be helpful for the beginners and also for those who want to take a quick look at the important topics of Hive. SQL AGGREGATE FUNCTIONS AVG returns the average of a list CREATE TEMPORARY VIEW v AS SELECT c1, c2 FROM t; Create a temporary view WHEN. BEFORE –invoke before the event occurs. AFTER –invoke after the event occurs EVENT. INSERT –invoke for INSERT. UPDATE –invoke for UPDATE. DELETE –invoke for DELETE TRIGGERTYPE. FOR.
Mastering Data science involves understanding of statistics, mathematics, programming knowledge especially in R, Python & SQL and then deploying a combination of all these to derive insights using the business understanding & a human instinct—that drives decisions.
Here are the cheat sheets by category:
Cheat sheets for Python:
Python is a popular choice for beginners, yet still powerful enough to back some of the world’s most popular products and applications. It's design makes the programming experience feel almost as natural as writing in English. Python basics or Python Debugger cheat sheets for beginners covers important syntax to get started. Community-provided libraries such as numpy, scipy, sci-kit and pandas are highly relied on and the NumPy/SciPy/Pandas Cheat Sheet provides a quick refresher to these.
- Python Cheat Sheet by DaveChild via cheatography.com
- Python Basics Reference sheet via cogsci.rpi.edu
- OverAPI.com Python cheatsheet
- Python 3 Cheat Sheet by Laurent Pointal
Cheat sheets for R:
The R's ecosystem has been expanding so much that a lot of referencing is needed. The R Reference Card covers most of the R world in few pages. The Rstudio has also published a series of cheat sheets to make it easier for the R community. The data visualization with ggplot2 seems to be a favorite as it helps when you are working on creating graphs of your results.
At cran.r-project.org:
At Rstudio.com:
- R markdown cheatsheet, part 2
Others:
- DataCamp’s Data Analysis the data.table way
Cheat sheets for MySQL & SQL:
For a data scientist basics of SQL are as important as any other language as well. Both PIG and Hive Query Language are closely associated with SQL- the original Structured Query Language. SQL cheatsheets provide a 5 minute quick guide to learning it and then you may explore Hive & MySQL!
- SQL for dummies cheat sheet
Cheat sheets for Spark, Scala, Java:
Apache Spark is an engine for large-scale data processing. For certain applications, such as iterative machine learning, Spark can be up to 100x faster than Hadoop (using MapReduce). The essentials of Apache Spark cheatsheet explains its place in the big data ecosystem, walks through setup and creation of a basic Spark application, and explains commonly used actions and operations.
- Dzone.com’s Apache Spark reference card
- DZone.com’s Scala reference card
- Openkd.info’s Scala on Spark cheat sheet
- Java cheat sheet at MIT.edu
- Cheat Sheets for Java at Princeton.edu
Cheat sheets for Hadoop & Hive:
Hadoop emerged as an untraditional tool to solve what was thought to be unsolvable by providing an open source software framework for the parallel processing of massive amounts of data. Explore the Hadoop cheatsheets to find out Useful commands when using Hadoop on the command line. A combination of SQL & Hive functions is another one to check out.
Cheat sheets for web application framework Django:
Django is a free and open source web application framework, written in Python. If you are new to Django, you can go over these cheatsheets and brainstorm quick concepts and dive in each one to a deeper level.
- Django cheat sheet part 1, part 2, part 3, part 4
Cheat sheets for Machine learning:
We often find ourselves spending time thinking which algorithm is best? And then go back to our big books for reference! These cheat sheets gives an idea about both the nature of your data and the problem you're working to address, and then suggests an algorithm for you to try.
- Machine Learning cheat sheet at scikit-learn.org
- Scikit-Learn Cheat Sheet: Python Machine Learning from yhat (added by GP)
- Patterns for Predictive Learning cheat sheet at Dzone.com
- Equations and tricks Machine Learning cheat sheet at Github.com
- Supervised learning superstitions cheatsheet at Github.com
Cheat sheets for Matlab/Octave
MATLAB (MATrix LABoratory) was developed by MathWorks in 1984. Matlab d has been the most popular language for numeric computation used in academia. It is suitable for tackling basically every possible science and engineering task with several highly optimized toolboxes. MATLAB is not an open-sourced tool however there is an alternative free GNU Octave re-implementation that follows the same syntactic rules so that most of coding is compatible to MATLAB.
Cheat sheets for Cross Reference between languages
Related:
Do you want to learn SQL online? Where do you start? There are many choices on the internet, and it can be hard to decide. But don’t worry—I tested and compared three major platforms to help you find the best place to learn SQL online!
E-learning is on the rise. It gives us infinite possibilities of growing our professional careers without leaving our homes. And increasing our competencies is especially important now that the labor market has become dynamic and unstable.
That’s why you may want to learn SQL online using an online learning platform. It’s a great choice! Interactive online learning environments make learning SQL far more practical than standard courses. And additional resources make it even more fun and effective.
The problem is that there are many platforms to choose from, and you probably are wondering which is the best site to learn SQL. Don’t worry, I’ll give you a hand.
I tried out three major online platforms for learning SQL: LearnSQL.com, DataCamp, and Codecademy. Below, you’ll find my complete comparison covering aspects such as teaching methods, UX, learning resources, and pricing. Let's get started!
Learning SQL Platform: LearnSQL.com
LearnSQL.com only offers courses in SQL, which makes it a perfect match for those looking for a SQL-specialized platform. All of the courses are written by experienced SQL engineers.
A great thing about this platform is that the courses are focused on practice. Students get some theory and tons of real-world exercises to help you learn SQL in a practical way.
Course Offering
As I’ve mentioned, LearnSQL.com only teaches SQL skills, but you can choose from a variety of courses. They’re grouped into paths, tracks, and mini tracks. However, it doesn’t prevent you from learning SQL with a single course.
If you’re a data analysis newbie or a basic-level programmer, you’ll benefit most from the Analytical Path. It teaches SQL querying and reporting for analyzing datasets and getting key insights from data. Its main track, SQL from A to Z, consists of seven courses designed for students learning SQL from scratch. Finishing this track takes approximately two weeks, and it lets you work with data independently.
Do you want to see if data analysis is for you? Take a look at the SQL Basics course—it’ll help you learn the absolutely necessary fundamentals in approximately 10 hours. Then, you can decide if you want to dive deeper.
Python For Data Science Cheat Sheet Datacamp
All of the courses on this platform have three versions: Standard SQL, Microsoft Server SQL, and PostgreSQL. These are different “dialects” of SQL (i.e., varieties used in different database management systems). They’re mostly similar but differ in some built-in functions, naming conventions, and error messages.
It’s super useful that LearnSQL.com allows you to choose which version. Once you learn Microsoft Server SQL, it’s pretty annoying to switch to PostgreSQL. Most programming platforms offer just one of the dialects without referencing to the others.
Other courses powered by LearnSQL.com cover practical topics such as generating SQL reports or analyzing revenue trends (especially useful for business professionals). There’s also a special course with only exercises called SQL Practice Set—I strongly recommend you to take it once you finish learning SQL at the basic level.
Programming is like sport: you need training and practice to become a professional. The same goes for learning SQL and writing code.
Currently, LearnSQL.com offers 11 learning tracks (six basic and five advanced) and 29 individual courses, but their developers are continually working on adding more courses. I recommend visiting their page regularly to stay up-to-date.
Teaching Method
Learning SQL with this platform is very practical because all courses feature loads of exercises. They’re based on real-world examples, mainly from the business field (so you’ll work with revenue spreadsheets, HR databases, and so on). If you’re seeking an analytical job within business operations or want to learn SQL online to power up your business skills, you’ll find it very useful.
The courses on LearnSQL.com include a number of lessons followed by either a quiz or a summary, serving as a quick recap of what has been learned. New concepts are explained through short descriptions with examples.
If you prefer extensive theoretical explanations, you may find them scarce. But it’s worth remembering that programming is all about practice, so it’s good to get down to coding ASAP. I found all of the recaps crystal clear and didn’t have additional questions (but if you do have them, you can always ask LearnSQL.com specialists using the Disqus tab).
Another good thing about learning SQL with this platform is that you write the code yourself. Some e-learning platforms teach programming by giving out strings with blank spaces to fill in. It may seem helpful, especially for beginners, but to become skillful at any programming language, you need to write thousands of lines yourself.
User Experience
Creating an account on this platform takes seconds (yes, seconds). You can use your Google or Facebook profile or simply create a new one. Once set up, you can use it to take a look at some free exercises from your chosen course.
LearnSQL.com provides an interactive programming environment, which means you don’t have to install a database management system on your device. You write and execute your code directly in the browser and get instant feedback if anything’s wrong.
The platform is easy to navigate and intuitive. The interactive console also works smoothly. Whenever you get stuck, you can either get a hint or see the full answer, but in most cases, the error messages displayed after running your code are enough.
Spark Dataframe Cheat Sheet
Last but not least: there’s a dark mode! Most users, including me, prefer working on a dark interface. Surprisingly, not all platforms provide it.
SQL Focus
As I‘ve said, on this platform, you can only learn SQL. It doesn’t provide courses in other languages, which makes it unique on the e-learning market, which is full of all-in-one solutions.
If you’ve decided to learn SQL, a specialized platform like this one is a great choice. Specialization provides high-quality content created by professionals in the chosen field (on LearnSQL.com, they’re delivered by experienced SQL developers).
Pandas Python Dataframe Cheat Sheet
Additional Resources
LearnSQL.com offers an extensive library of articles explaining how to learn SQL online quickly and efficiently. Apart from learning tips, you’ll find additional explanations regarding useful SQL functions, developers’ stories, or advice on how to write code that’s easy to read. New articles are published almost every day!
There’s also a special section called Cookbook. It’s a collection of simple, recipe-like entries covering single SQL problems and their solutions. They guide you step-by-step through the coding challenge you’re facing and give you a clear solution (with fragments of code presented). It’s super useful if you’re searching for a quick solution. And they’re sorted by database types (Standard SQL, MS SQL, etc.) to help you find your answer quickly.
Pricing Model
To learn SQL online with this platform, you need to create an account (as I’ve said, it takes seconds). It gives you free access to several exercises from the first lessons of each course so that you can test them out. If you like the platform and want to start learning SQL for real, you’ll need to purchase a subscription plan:
- Basic for $39/month (billed monthly): access to 29 courses and 13 tracks
- Premium for $29/month (billed monthly): access to the Basic plan courses and tracks plus monthly coding challenges, premium content, and priority support
![Sql Cheat Sheet Datacamp Sql Cheat Sheet Datacamp](/uploads/1/3/7/4/137425351/949168206.png)
Mind that the Basic plan has no long-term commitment unlike the Premium plan that needs to be purchased for six months. However, the Premium plan is more affordable. Check the details of both here.
There is also a Business plan for enterprise clients. It doesn’t have fixed pricing, so you will need to contact the LearnSQL.com team for details. It provides access to custom courses, an early access program, a dedicated success manager, and an additional learning management portal, which allows you to track user progress.
Learning SQL Platform: DataCamp
DataCamp is a platform that offers numerous basic and advanced courses in data science. They cover nine technologies, including SQL. The courses are taught mainly by internal DataCamp developers but also university professors and business professionals.
Learning SQL with this platform is slightly different from LearnSQL.com because DataCamp doesn’t focus exclusively on SQL. Plus, it uses a different learning method.
Course Offering
On DataCamp, you can browse the course catalogue by technology or topic. There are nine technologies to choose from and a separate category for theoretical courses. The topics cover data engineering, data manipulation, statistics, reporting, etc.
DataCamp offers career tracks and skill tracks. They make learning SQL more goal-oriented, and you need to know what you’re looking for. There’s only one career track for those interested in learning SQL called Data Analyst with SQL Server. It takes approximately 45 hours to complete and includes 11 courses.
As far as skill tracks, new learners will benefit most from SQL Fundamentals or SQL Server Fundamentals, depending on the chosen database. Unfortunately, DataCamp skill tracks don’t cover other SQL variations (e.g., the popular PostgreSQL).
The platform has 22 courses for learning SQL at basic and more advanced levels. For beginners, I recommend Introduction to SQL or Introduction to SQL Server, which teach basic data analysis concepts and writing elementary queries in Standard SQL or SQL Server.
Teaching Method
Learning SQL on DataCamp is slightly different from LearnSQL.com. DataCamp courses start with short videos with simple slides that are commented on by a teacher. After this theoretical introduction, you move on to exercises with written explanations. While learning SQL, you can go back to the video or view the slides.
DataCamp courses consist of several chapters, including lessons and a summary. Most lessons end with a final exercise that’s slightly more complex than the others. The explanations are clear, so doing the exercises shouldn’t be problematic.
If you’re an auditory learner, you’ll probably find the videos cool. For me, it’s easier to follow written text while learning SQL—I need to focus on new concepts and give myself enough time to grasp them. That’s why I didn’t find the videos very useful and preferred to go directly to the descriptions.
On DataCamp, you don’t really write code yourself. When learning SQL with the basic courses, you instead fill in blank spaces with single words or clauses. You’re provided most of the necessary strings and instructions explaining what each line of your code should do.
It’s at the same time good and bad: good because it makes learning SQL easier and helps you understand everything fully, but bad because it doesn’t provide enough practice. I prefer to write code myself, so I mostly deleted the code provided in the lessons and wrote it again.
User Experience
Creating an account on DataCamp is super quick. You can either provide your email and create a password or use your Google, Facebook, or LinkedIn account. After logging in for the first time, the system asks you about your preferred technology and the topic you’re interested in (e.g., reporting, Machine Learning, business analytics, etc.) and suggests suitable courses.
You can start learning instantly, but the free account only gives you access to the first chapter of each course. If you already have some SQL skills, you can test your knowledge with DataCamp’s assessment tool.
Using DataCamp is simple and intuitive, and navigating through the website is easy. However, at first, you may have problems understanding what each page contains because there are many of them: career tracks, skill tracks, courses, practice, projects…
Interestingly, the platform offers many additional resources (I’ll explain it later on), but not all of them are accessible from the user dashboard. To access them, you have to enter the Community section from the home page, which is visible after logging out.
Just like LearnSQL.com, DataCamp provides an interactive environment that allows writing and executing queries in your browser. While learning SQL with its courses, you get instant feedback on what’s wrong with your code, and you can also use hints.
And there’s a dark mode! Unfortunately, it doesn’t cover the whole interface—the console gets dark, but the instructions remain light. Pity!
SQL Focus
DataCamp is a platform for learning various analytical languages. It’s a one-stop-shop for data science professionals, not only those interested in learning SQL. It offers courses in nine technologies, including popular languages like R, Python, and Git, and some additional chapters providing theoretical background for business professionals.
While you’re browsing the course catalogue, it becomes clear that the platform is not focused on SQL. It offers 22 courses in SQL, approximately 120 in Python, and even more in R. The other technologies have even fewer courses than SQL, so I’d say that it’s specialized in Python and R.
Additional Resources
DataCamp has an extensive section of additional resources. First of all, it offers Practice and Projects: additional learning materials for practicing newly acquired skills. Practice sets include quizzes while Projects are…well, projects that are based on real-world data. Unfortunately, because DataCamp doesn’t focus on SQL, there are only two Practice sets and one Project for this SQL.
There’s also a separate page called DataCamp Community where you’ll find more resources. It features a data science blog (for basic and advanced users), a podcast (definitely for advanced users), cheat sheets (mainly for Python and R; no SQL here), and step-by-step tutorials (mainly for Python programmers; I found only a few for SQL).
There are also webinars and white papers on various topics related to data science in general, but you have to leave your company data to download them (surprising—I’ve already paid for the Premium plan!). There’s also a DataCamp Slack community that you can join and a section with open source courses made by DataCamp users (you can create your own as well).
As I’ve said, most of the resources are not available from the user dashboard, so make sure to access them directly or from the DataCamp homepage.
Pricing Model
To learn SQL on DataCamp, you need to create a free account. Once you have it, you get access to the first chapter of each course, challenges, a one-time skill assessment, and seven projects. To continue learning, you need to purchase a subscription plan:
- Basic for $25/month: access to free content plus 44 courses (in Python and R only; there are no SQL courses in this plan), two career tracks, unlimited skill assessments, and the Slack chat
- Premium for $33.25/month: access to all courses, skill tracks, and projects plus priority support
There’s also a Professional plan for $300/year that gives you even more benefits, but a beginner won’t need it. The same goes for the Enterprise plan for business users (no fixed pricing; contact DataCamp for details). You’ll find the description of all plans here.
Learning SQL Platform: Codecademy
Codecademy is another one-stop-shop platform for basic and advanced developers. Apart from learning SQL, you can use it to dive into web development, design, other data science technologies, and more. It offers 13 programming languages in total, which is a robust course catalogue.
Course Offering
On Codecademy, you can browse the course catalogue by subject (web development, programming, data science, etc.) or language. There are 13 technologies to choose from, including SQL.
The courses are grouped into career paths and skill paths. The only career path including SQL, Data Science, also covers Python, Data Visualization, and Machine Learning. There’s also one SQL skill path called Analyze Data with SQL that takes approximately six weeks to complete (counting lessons, articles to read, quizzes to take, and projects to complete).
Codecademy offers three SQL courses in total: one elementary and two slightly more advanced (I’d call them intermediate). If you want to learn SQL online from scratch, you should take Learn SQL, which covers basic query concepts.
However, if you’re not sure if SQL is the one, Codecademy will help you choose your technology with a short quiz assessing your personal abilities. I’m not sure about its usefulness though. I took it and got similar results in all four programming language categories.
The platform doesn’t offer any courses for learning SQL at an advanced level.
Teaching Method
On Codecademy, you learn SQL with textual explanations. The teachers (developers collaborating with the platform from around the world) provide you with simple descriptions of new concepts and sample code lines. After getting familiar with a new concept, you have to complete an exercise.
Codecademy courses include several lessons and a review summarizing key concepts. Most of these lessons feature a cheat sheet with SQL functions, keywords, etc. (they’re nice, but not formatted for printing—pity!).
After completing a course, you’re encouraged to do an additional project. I generally found the instructions clear, but sometimes I did have questions. In such cases, Codecademy redirected me to its user forum where I was likely to find an answer.
On Codecademy, unlike at DataCamp, you write the code yourself from scratch.
![Camp Camp](/uploads/1/3/7/4/137425351/983777794.jpg)
User Experience
Signing up for Codecademy is super quick. The platform allows you to create an account using your LinkedIn, Google, Facebook, GitHub, or Twitter profile. After logging in, you can immediately get down to learning SQL with the basic course, but you only have access to the first lesson. For more, you need to purchase a paid plan.
Navigating through the website is rather easy. The user dashboard is simple as well, but I found the homepage a bit stacked. The platform shows you your courses, suggested practice and projects, new content, support tabs, and community hyperlinks all on one page! It’s a bit overwhelming.
Codecademy also provides an interactive coding environment that doesn’t require installing databases on your computer. While doing exercises, you make use of a built-in console that works smoothly.
If you get stuck, you can get a hint, take a look at a cheat sheet, or look for an answer in the Codecademy community forum. Just like on other platforms, you get instant feedback on what’s wrong with your code.
Interestingly, Codecademy has only a dark mode! However, it works like the one at DataCamp: the console is dark while instructions remain light.
SQL Focus
Codecademy is similar to DataCamp: it’s an all-in-one platform. However, it’s not for data science only. Apart from learning SQL, you can use it for learning other programming languages such as Java, Ruby, C++, PHP, or Swift. Python and JavaScript have the most courses.
Codecademy has only three courses devoted to SQL, which is the lowest number from the three platforms I’ve tested. It clearly shows that SQL isn’t its primary focus.
Additional Resources
Codecademy offers some additional resources that make learning SQL more effective. First of all, it features projects based on genuine databases and practice sets including quizzes. You can use them to practice your new SQL skills.
The platform also has a blog section with entries on learning programming online, new courses, and news from the tech world. There are also posts about data science and developing in general, which are targeted to newbies. You can get some knowledge from the Codecademy articles page with content grouped by languages. Unfortunately, there is no SQL section.
There is also a forum section where you can ask questions and discuss ideas. That’s where the lessons redirect to.
Pricing Model
To learn SQL online with Codecademy, you need to create a free account. It gives you full access to basic courses (obviously, there are only a few of them, and they’re elementary). To enjoy more benefits, you will need to purchase a subscription plan:
Sql Cheat Sheet Datacamp
- PRO for $19.99/month: access to non-basic courses, mobile practice, projects, and peer support
The platform gives you a chance to test the PRO plan with a 7-day free trial. There’s also a plan called Teams for enterprise clients without fixed pricing (contact Codecademy for details). Check out the plans here.
Choose the Best Place to Learn SQL Online
I hope that my comparison will help you choose your platform for learning SQL online. All of them have their pros and cons, so think about your learning priorities, set your goals, and…learn!
Below, you’ll find a short summary of my comparison: