MySQL Tutorials - Herong's Tutorial Examples - v4.46, by Herong Yang
ORDER BY Clause of a SELECT Statement
This section provides tutorial examples on how to use the ORDER BY clause to sort rows of the base table according to the given order.
"ORDER BY clause" modifies the base table by sorting rows according the specified order. "ORDER BY clause" syntax is:
ORDER BY order_exp, order_exp, ...
where "order_exp" specify a single order expression. If multiple order expressions are specified, the order expression on the left has higher precedence than the one on the right. This means the order expression on the right will only be used to sort rows that are having the same for the order expression on the left.
If ORDER BY clause is used with GROUP BY clause, it must contain only group columns or aggregate functions. For example, the following statement shows us which department has the oldest average age:
SELECT department, COUNT(name) AS numberOfEmployees, min(age) AS minimumAge, max(age) AS maximumAge, AVG(age) as averageAge FROM employee WHERE status='Active' GROUP BY department ORDER BY AVG(age) DESC
Another interesting function called FIELD() can also be used in the ORDER BY clause. FIELD(value, value_list) returns the position of a given value in a given value list. For example, if you want to return employees with first name of "Jean, Mary, John, Mike" and in this order, you can use the following SELECT statement:
SELECT name, department, age FROM employee WHERE name IN ('Jean', 'Mary', 'John', 'Mike') ORDER BY FIELD (name, 'Jean', 'Mary', 'John', 'Mike')
Table of Contents
MySQL Introduction and Installation
Introduction of MySQL Programs
Perl Programs and MySQL Servers
Java Programs and MySQL Servers
Character Strings and Bit Strings
Table Column Types for Different Types of Values
Using DDL to Create Tables and Indexes
Using DML to Insert, Update and Delete Records
►Using SELECT to Query Database
FROM Clause of a SELECT Statement
JOIN - Operation to Join Two Tables
JoinTable.sql - Example of Join Tables
WHERE Clause of a SELECT Statement
►ORDER BY Clause of a SELECT Statement
GROUP BY Clause of a SELECT Statement
Window Functions for Statistical Analysis
Use Index for Better Performance
Transaction Management and Isolation Levels
Defining and Calling Stored Procedures
Variables, Loops and Cursors Used in Stored Procedures
System, User-Defined and Stored Procedure Variables
Storage Engines in MySQL Server
InnoDB Storage Engine - Primary and Secondary Indexes
Performance Tuning and Optimization
Installing MySQL Server on Linux