Sorting data using SQL

Using the ORDER BY clause in SQL, it is easy and quick to sort data from a database. The ORDER BY clause in SQL can be used to sort data in either ascending or descending order depending on one or more columns.

The syntax for using the ORDER BY clause is as follows:

SELECT column1, column2, ... FROM table_name ORDER BY column1 ASC/DESC, column2 ASC/DESC, ...;

In this syntax, the FROM statement defines the table name, and the SELECT statement specifies the columns to obtain from the table. The column(s) to sort by and whether to sort in ascending (ASC) or descending (DESC) order are specified in the ORDER BY statement.

Sorting by a Single Column

Suppose there is a table called employees with columns employee_id, first_name, last_name, hire_date and salary.

Sort this table by the last_name column in ascending order using the following SQL query:

SELECT * FROM employees ORDER BY last_name ASC;

This query returns all the columns from the employees table sorted in ascending order by the last_name column.

Sorting by Multiple Columns

Sorting by multiple columns is useful when you need to sort data by more than one criterion.

For example, suppose sorting the employees table by last_name and then by hire_date.

See the following SQL query:

SELECT * FROM employees ORDER BY last_name ASC, hire_date ASC;

This query returns all the columns from the employees table sorted in ascending order by the last_name column and then by the hire_date column.

Sorting in Descending Order

By default, SQL sorts data in ascending order and for descending order use DESC keyword.

For example, suppose sorting the employees table by salary in descending order.

Use the following SQL query:

SELECT * FROM employees ORDER BY salary DESC;

This query returns all the columns from the employees table sorted in descending order by the salary column.