Picture by Creator
The web is brimming with sources for studying SQL. Most of them, in fact, require paying for information. These sources additionally primarily educate you fundamental or, at greatest, intermediate SQL.
The query is, learn how to study SQL and do it free of charge. Are there any sources in any respect that may educate you superior SQL with out paying?
Sure, there are. Actually, there are at the least 5, as I found.
Earlier than on the lookout for the programs, I needed to outline what superior SQL means.
What’s Superior SQL?
It’s not straightforward to pin this down, as totally different specialists have totally different views (and instructing expertise) on which SQL ideas could be thought-about superior.
Nevertheless, I believe it’s secure to say that these matters are superior SQL:
- JOINs
- CTEs
- Recursive CTEs
- Subqueries and Correlated Subqueries
- Window Capabilities
- Pivoting and Unpivoting Knowledge
- Hierarchical Queries
- Views
- Saved & Person-Outlined Procedures and Capabilities
- Triggers
- Momentary Tables
- Indexes
- Knowledge Normalization
- Efficiency Optimization
The listing is incomplete, nevertheless. Another matters that additionally belong to superior SQL could be added. How are you going to say in the event that they’re superior? I’ve a extremely unscientific however environment friendly technique: should you don’t know what a specific matter means, it’s probably superior SQL.
Free Sources for Superior SQL
Picture by creator
The sources I listing right here cowl some or a lot of the superior SQL ideas I discussed earlier. For those who mix these sources, your superior SQL information can grow to be much more healthful. Sure, I do know it requires a bit extra effort, however hey, these are all free. What did you anticipate?
1. Mode SQL Tutorial
Hyperlink to useful resource: Mode Analytics SQL Tutorial
Description: This tutorial teaches you superior SQL within the Mode BI software. No want to fret that you just’ll should study yet one more SQL taste; Mode makes use of commonplace SQL.
All of the ideas are defined theoretically intimately. In every lesson, there are additionally interactive workout routines the place you’ll be able to apply fixing issues by writing SQL queries and verify the solutions.
Talking of ideas, you’ll find out about subqueries, window features, tuning SQL queries, and pivoting knowledge. As well as, there are classes about knowledge sorts, date codecs, and string features.
For those who really feel you’re fighting a few of the much less superior matters in these classes, you’ll be able to at all times revisit them within the Primary SQL and Intermediate SQL sections of the tutorial.
2. StanfordOnline: Databases: Superior Subjects in SQL
Hyperlink to useful resource: edX
Description: This course is considered one of 5 programs on databases provided by Stanford College and hosted by edX.
Of the superior matters, you may be taught indexing to enhance question efficiency, transactions, database constraints and triggers, and views.
It is going to take you two weeks to finish the course, with 8-10 hours per week.
As well as, you’ll be able to take programs on OLAP and recursion, modeling and principle, and semistructured knowledge should you’re interested by these matters.
3. Kaggle Superior SQL
Hyperlink to useful resource: Kaggle Superior SQL
Description: Kaggle’s cute little course will take solely 4 hours to finish. It covers JOINs and UNIONs, analytic (or window) features, nested and repeated knowledge, and tips about writing environment friendly queries.
Every lesson supplies detailed theoretical explanations complemented by sensible examples. On the finish of every lesson, you will see that a hyperlink to a piece that exams your understanding by providing you with a number of workout routines to resolve by writing code.
4. Superior SQL (Summer time 2020)
Hyperlink to useful resource: YouTube
Description: This video course consists of lectures by the Database Analysis Group on the College of Tübingen, Germany.
There are 58 movies, most of them round a half-hour. They cowl matters reminiscent of subqueries, set operations, GROUP BY extensions, knowledge sorts, arrays, window features, user-defined features, recursive CTEs, and plenty of, many extra.
5. SQL for Net Nerds
Hyperlink to useful resource: Philip Greenspun’s private web site
Description: This on-line guide was written by Philip Greenspun, a US laptop scientist and educator.
It combines theoretical and sensible explanations by means of code and real-world examples. Most examples use the info mannequin for internet providers and are written in Oracle SQL dialect.
This useful resource will educate you triggers, views, timber, database tunings, and plenty of extra.
Bonus: Virtually Free Sources
As a bonus, I needed so as to add two nearly free sources: StrataScratch (sure, the platform I based) and LeetCode, two platforms with precise SQL coding interview questions.
Virtually free, as in very low cost? No, free in a means that they require a paid subscription to entry all questions but in addition have a considerable variety of freemium questions.
We’ve 75 free questions at StrataScratch, most of them of medium or exhausting problem. You’ll undoubtedly discover a strong variety of them to check your superior SQL information. To make looking simpler for you, there’s an in depth filter the place you’ll be able to filter by matter, problem, and firm, amongst different issues.
There’s additionally an interactive code editor for writing your answer in a number of SQL flavors (PostgreSQL, SQL Server, MySQL, and Oracle) and validating it. All of the questions have hints and official options with detailed explanations.
LeetCode has the identical variety of questions if I counted accurately. Nevertheless, they’re, typically, categorized as straightforward or medium, which might make on the lookout for superior matters a bit of trickier. However, I’m certain you’ll be capable of discover some good questions for practising the matters I discussed originally of this text. Like StrataScratch, LeetCode additionally has detailed options and an interactive code editor permitting code-writing in a number of SQL dialects.
Conclusion
There it’s – 5 sources that may educate you superior SQL strategies and do it free of charge. They’re additionally high quality sources, which makes for higher studying.
Three sources are basic on-line SQL programs that cowl totally different superior matters. I threw within the combine one thing totally different, too: one YouTube course by a high German college and one on-line guide by a acknowledged knowledgeable and educator.
A number of the matters lined in these sources overlap, however some are distinctive to every useful resource. For those who don’t discover what you’re on the lookout for in a single course, you’ll be able to at all times mix the sources and fill within the gaps.
As a bonus, there are two interview query platforms, StrataScratch and LeetCode, that supply some questions free of charge.
I hope you’ll discover all these a helpful useful resource for studying superior SQL. Glad studying!
Nate Rosidi is a knowledge scientist and in product technique. He is additionally an adjunct professor instructing analytics, and is the founding father of StrataScratch, a platform serving to knowledge scientists put together for his or her interviews with actual interview questions from high firms. Nate writes on the most recent traits within the profession market, offers interview recommendation, shares knowledge science initiatives, and covers every part SQL.