Getting Started with SQL and Databases: Managing and Manipulating Data with SQL

© The Author(s), under exclusive license to APress Media, LLC, part of Springer Nature 2023

M. SimonGetting Started with SQL and Databaseshttps://doi.org/10.1007/978-1-4842-9493-2_4

4. Ordering Results

Mark Simon¹  

(1)

Ivanhoe VIC, VIC, Australia

 

A Relational Database is based on a number of mathematical principles, including the notion that a table is a set of rows. Two important properties of mathematical sets are

• A set has no duplicates.

• A set is not ordered.

We will discuss the question of duplicates later, but for now let’s have a look at row order.

SQL does not specify how data is to be stored, as that is a matter for the DBMS software. Neither does it specify in what order data should be fetched.

However, you do have the option to specify a row ...