A majority of SQL focuses on querying data. Makes sense, as that is one of the main purposes of a database!
In this section we’ve collected several categories related to querying, namely:
- Sorting – Ordering rows by columns and expressions and selecting the top or bottom results.
- Filtering – The ability to use Boolean logic to select one set of rows with a result over another.
- Group and Summarize – Use GROUP BY and HAVING to calculate summary data such as averages, summations, minimum and maximum values.
If you’re new to SQL, I would recommend you join our Essential SQL learning group on FB.
All the examples for this lesson are based on Microsoft SQL Server Management Studio and the sample databases AdventureWorks and WideWorldImporters. You can get started using these free tools using my guide Getting Started Using SQL Server