For an instructor lead, in-depth look at learning SQL click below.
Welcome! If you’re new to SQL (Structured Query Language), this fun, interactive tutorial is perfect for you. Let’s dive into this powerful language used to communicate with databases and learn the basics step-by-step.
What is SQL?
SQL stands for Structured Query Language. It’s a standard language for interacting with databases. SQL helps us access, manipulate, and execute queries on the data stored in a database.
Getting Started: SELECT Statement
We will start with the most basic SQL command – the SELECT statement. The SELECT statement is used to select data from a database. The data returned is stored in a table called result-set.
Here is an example:
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SELECT column1, column2 FROM table_name; |
This will select column1 and column2 from the table named ‘table_name’
Using WHERE: Filtering Data
Using the WHERE clause in SQL, you can filter the results of a SELECT statement. Let’s say we want to retrieve employees from a ‘Employee’ table who have a salary greater than 50000.
Here’s the SQL code:
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SELECT * FROM Employee WHERE Salary > 50000; |
JOIN: Bringing Tables Together
When you want to combine rows from two or more tables, based on a related column, you use the JOIN keyword. Assume we have a ‘Orders’ table and a ‘Customers’ table. We could combine these two tables together with the following SQL keyword:
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SELECT Orders.OrderID, Customers.CustomerName FROM Orders INNER JOIN Customers ON Orders.CustomerID = Customers.CustomerID; |
That’s it for now! Remember, practice makes perfect. Feel free to experiment with these commands, adjust the parameters, and observe the different outcomes. SQL is a powerful language, and with a little time and patience, you can use it to harness your data’s full potential.
Enjoy exploring SQL!