Learn SQL: Free SQL Resources, Tutorials, Videos & Classes

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SQL SELECT Tutorial

Simple Tutorial on how to use the SELECT statement in SQL

SQL ORDER BY Tutorial

Learn to use the ORDER BY function in SQL to sort data with our tutorial and screenshots.

SQL WHERE Tutorial

This tutorial walks through the basics of the WHERE statement in SQL and an example of how to use it.

What is SQL?

SQL (Structured Query Language) is a database programming language designed to communicate to with a database.

SQL can do the following:

Create new databases

Delete records

Create new tables in a database

Execute queries against a database

Insert records in a database

Create stored procedures

Retrieve data from a database

Create views

Update records

Set permissions on tables, procedures, and views

Even if SQL is a standard, many of the database systems that exist today implement their own version of SQL language.

Why Use SQL?

We can store data in systems such as Excel or Google Sheets. However, SQL Server (or other database management systems) is a better tool for the job. Excel is great for spreadsheets and explaining data analytics, but its limited in the amount of data it can stored. It’s easy to make accidental changes to data and it’s hard to replicate an old analysis of new data. Mostly, the larger the amount of data, the slower it becomes. Likewise, it is cumbersome to share giant spreadsheets over email.

SQL also separates analysis from data. When using SQL, your data is stored separately from your analysis. Instead of emailing a massive Excel file, you can send tiny plain text files containing the instructions for your analysis. Each team member can have access to the same data, so they can run your analysis on their own. They don't have to manage file versions or risk corrupting the data, and they can re-run it on any other data. SQL can run on databases with billions of rows and columns. Simply, SQL is much faster than that's before the pivot tables, multiple tabs, and functions you're probably using.

Learn SQL in Hands-on Classes

These guides are helpful resources for before or after our interactive, SQL classroom training in NYC. Register today and master this powerful database programming language.