SQL Cheat Sheet
SQL Basics: An Introduction
Structured Query Language (SQL) is a programming language used to manage and manipulate relational databases. SQL allows you to extract and manipulate data stored in a database, as well as perform various operations such as adding, updating, and deleting data.
SQL is commonly used in web development, data analysis, and business intelligence. It’s a valuable tool for anyone who works with large amounts of data and needs to organize and extract meaningful insights from it.
To get started with SQL, you’ll need to know some basic commands. Here are a few essential SQL commands to get you started:
SELECT
Is used to extract data from a database. You can select specific columns or all columns using the “*” wildcard.
Example:
SELECT * FROM customers;
DISTINCT
Is used to return only distinct (different) values. This command is useful when you want to eliminate duplicate data from a result set.
Example:
SELECT DISTINCT city FROM customers;
WHERE
Is used to filter data based on a condition. You can use operators such as “=”, “<>”, “>”, “<“, “>=”, “<=”, “LIKE”, and “IN” to compare data.
Example:
SELECT * FROM customers WHERE city = 'New York';
ORDER BY
Is used to sort the result set in ascending or descending order based on a specified column.
Example:
SELECT * FROM customers ORDER BY last_name ASC;
LIMIT
Is used to limit the number of rows returned in the result set.
Example:
SELECT * FROM customers LIMIT 10;
These are just a few of the basic SQL commands that you’ll need to know to get started. With these commands, you can begin to extract and manipulate data stored in a database. As you become more familiar with SQL, you can start using more advanced commands to perform more complex operations.