For an instructor lead, in-depth look at learning SQL click below.
Welcome to our SQL Crash Course! Whether you are a novice aspiring to learn the basics of SQL, or an experienced programmer aiming to sharpen your skills, this post is designed for you. This tutorial will walk you through basic to advanced SQL commands.
Structured Query Language: An Introduction
Structured Query Language, better known as SQL, is a standardized programming language that allows you to interact with databases. SQL is used to create, retrieve, update, and delete data from a database.
Understanding Tables & SQL Basics
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-- This is how you create a new table CREATE TABLE Employees ( ID int, Name varchar(255), Age int, Address varchar(255), Salary decimal ); |
This SQL statement creates a new table named “Employees”. You define the table name and its columns’ names and their data types. Here, the table “Employees” with the fields ID, Name, Age, Address, and Salary is created.
SQL SELECT Statement
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-- Select all fields from a table SELECT * FROM Employees; |
This SQL statement selects all data from the “Employees” table. The asterisk (*) is a wildcard character that means “everything”.
SQL WHERE Condition
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-- Select data from a table with a condition SELECT * FROM Employees WHERE Age > 30; |
In this SQL statement, only records of “Employees” where the “Age” is over 30 are fetched.
SQL UPDATE Statement
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-- Update a field in the table UPDATE Employees SET Salary = 50000 WHERE ID = 1; |
This SQL statement updates the “Employees” table and sets the Salary for employee with ID = 1 to 50000.
SQL DELETE Statement
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-- Delete a specific record from the table DELETE FROM Employees WHERE ID = 1; |
This SQL statement deletes the employee record where the ID equals 1 in the “Employees” table.
Conclusion
SQL is an incredibly powerful tool, and the above examples just the start. I hope it was helpful as an introduction to SQL and how to use basic commands. I encourage you all to practice and try writing other SQL commands on your own and explore more advanced features. Remember: Practice is key to becoming an expert!
Happy coding!
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