`ORDER BY` Clause in DBMS (MySQL) [ English ]

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Introduction

When retrieving data from a table using the SELECT statement, the results may not appear in any particular order. In many situations, users need the data to be arranged in a specific order such as ascending or descending.

The ORDER BY clause is used to sort the result of a query based on one or more columns. This helps in organizing data for easier reading and analysis.

Definition

The ORDER BY clause is used in SQL to sort the records retrieved from a table in ascending or descending order based on one or more columns.

Syntax

SELECT column1, column2, ...
FROM table_name
ORDER BY column_name [ASC | DESC];

Where:

• column1, column2 – Columns to be retrieved.
• table_name – The name of the table.
• column_name – The column used for sorting.
• ASC – Sorts data in ascending order (default).
• DESC – Sorts data in descending order.

Example Table

Suppose we have a table named students.

Example 1: Sorting in Ascending Order

SELECT * FROM students
ORDER BY age ASC;

Output

The records are arranged from lowest age to highest age.

Example 2: Sorting in Descending Order

SELECT * FROM students
ORDER BY age DESC;

Output

The records are arranged from highest age to lowest age.

Sorting by Multiple Columns

It is also possible to sort records using more than one column.

SELECT * FROM students
ORDER BY course ASC, age DESC;

In this example:

• Records are first sorted by course.
• If multiple students belong to the same course, they are sorted by age in descending order.

Important Notes

• The default sorting order is ascending (ASC).
• The ORDER BY clause is usually written after the WHERE clause.
• Multiple columns can be used for sorting.

Example:

SELECT * FROM students
WHERE course = 'BCA'
ORDER BY age;

Key Points

• ORDER BY is used to sort query results.
• Sorting can be ascending (ASC) or descending (DESC).
• The default order is ascending.
• Multiple columns can be used for sorting.

Summary

The ORDER BY clause is used to arrange the results of a SQL query in a specific order. By sorting data based on one or more columns, users can easily analyze and interpret information stored in a database.