For an instructor lead, in-depth look at learning SQL click below.
Welcome! Whether you’re a complete beginner or have dabbed a bit in SQL, this blog post is designed to guide you through the basics of SQL, giving you a strong foundation to advance to higher levels of data analytics using SQL. Let’s get started!
What is SQL?
SQL (Structured Query Language) is a programming language used to manage data held in a relational database management system (RDBMS). SQL lets you access and manipulate databases, adjusting their structure and content based on your needs.
Your first SQL statement
The most basic command you can start with is SELECT. Suppose we’ve a students database and you want to view all the data stored, your SQL statement would look like this:
|
1 2 3 |
SELECT * FROM Students; |
In this query, “SELECT *” tells SQL to select all columns, and “FROM Students” tells it from which table. The semicolon (;) signifies the end of the command.
Selecting specific columns
What if we only want to see the Names and Grades of the students? We simply just specify these column names in our SELECT statement, like this:
|
1 2 3 |
SELECT Name, Grade FROM Students; |
Filtering with the WHERE Clause
How about if we want to select students who got grades more than 90? For this, we can use the WHERE clause for filtering:
|
1 2 3 |
SELECT Name, Grade FROM Students WHERE Grade > 90; |
Sorting with the ORDER BY clause
We can also order our results using ORDER BY clause. To order the students by name in ascending order (alphabetically), we can use:
|
1 2 3 |
SELECT Name, Grade FROM Students ORDER BY Name; |
Congratulations! You’ve officially written your first few SQL statements. It’s really just a starting point – there’s so much more to SQL like JOIN, GROUP BY, HAVING clauses and creation of databases and tables with DDL commands. But for now, keep practicing these basic commands until you’re comfortable. Happy querying!
.
Conclusion
SQL is a powerful language with a relatively simple syntax. Its mastery opens doors to roles like Database Administrators, Data Analysts, Back-end Developers, and many more. Most importantly, SQL allows us to channel the power of raw data into actionable insights. So keep practicing and soon, you’ll go from SQL beginner to SQL hero!