SQL ORDER BY
The ORDER BY clause is used in a SELECT statement to sort results either in ascending or descending order. Oracle sorts query results in ascending order by default.
Syntax for using SQL ORDER BY clause to sort data is:
FROM table_name [WHERE condition]
[ORDER BY column1 [, column2, .. columnN] [DESC]];
database table "employee";
For Example: If you want to sort the employee table by salary of the employee, the sql query would be.
SELECT name, salary FROM employee ORDER BY salary;
The output would be like
The query first sorts the result according to name and then displays it.
You can also use more than one column in the ORDER BY clause.
If you want to sort the employee table by the name and salary, the query would be like,
SELECT name, salary FROM employee ORDER BY name, salary;
The output would be like:
NOTE:The columns specified in ORDER BY clause should be one of the columns selected in the SELECT column list.
You can represent the columns in the ORDER BY clause by specifying the position of a column in the SELECT list, instead of writing the column name.
The above query can also be written as given below,
SELECT name, salary FROM employee ORDER BY 1, 2;
By default, the ORDER BY Clause sorts data in ascending order. If you want to sort the data in descending order, you must explicitly specify it as shown below.
SELECT name, salary
ORDER BY name, salary DESC;
The above query sorts only the column 'salary' in descending order and the column 'name' by ascending order.
If you want to select both name and salary in descending order, the query would be as given below.
SELECT name, salary
ORDER BY name DESC, salary DESC;
How to use expressions in the ORDER BY Clause?
Expressions in the ORDER BY clause of a SELECT statement.
For example: If you want to display employee name, current salary, and a 20% increase in the salary for only those employees for whom the percentage increase in salary is greater than 30000 and in descending order of the increased price, the SELECT statement can be written as shown below
SELECT name, salary, salary*1.2 AS new_salary
WHERE salary*1.2 > 30000
ORDER BY new_salary DESC;
The output for the above query is as follows.
NOTE:Aliases defined in the SELECT Statement can be used in ORDER BY Clause.