Oracle Order By Clause Use

**Understanding Oracle's ORDER BY Clause: A Comprehensive Guide for Beginners**


The ORDER BY clause is a powerful tool in SQL that allows you to sort the result set of a query based on one or more columns. For beginners diving into Oracle SQL, understanding how to use ORDER BY is crucial for organizing and presenting data effectively.


In this blog, we'll walk through the ORDER BY clause step by step, providing clear explanations and real-time examples to help new students grasp its concepts easily.

What is the ORDER BY Clause?


The ORDER BY clause is used to sort the rows returned by a SELECT statement.


It is used to sort the result output based on one or multiple columns either in ascending or in descending order.


By default, ORDER BY sorts in ascending order.


SELECT column1, column2


FROM table_name


ORDER BY column1 ASC;


Basic Usage of ORDER BY


Let's start with a simple example.


Suppose we have a table named `employees` with columns `employee_id`, `first_name`, and `salary`.


To retrieve all employees sorted by salary in ascending order:


SELECT first_name, salary


FROM employees


ORDER BY salary ASC;


Sorting in Descending Order


To sort the employees by salary in descending order:


SELECT first_name, salary


FROM employees


ORDER BY salary DESC;


Sorting by Multiple Columns


You can also sort by multiple columns.


For instance, if you want to sort employees first by department and then by salary within each department:


SELECT first_name, department, salary


FROM employees


ORDER BY department ASC, salary DESC;


Real-time Example: Sorting Products


Imagine you have a `products` table with columns `product_id`, `product_name`, and `unit_price`.


To display products sorted by unit price in descending order:


SELECT product_name, unit_price


FROM products


ORDER BY unit_price DESC;


Sorting Dates


ORDER BY can also handle date columns effectively.


Suppose you have an `orders` table with an `order_date` column.


To retrieve orders sorted by date in ascending order:


SELECT order_id, order_date


FROM orders


ORDER BY order_date ASC;


Handling NULL Values


When sorting columns that contain NULL values, Oracle places NULL values at the end of the result set when sorting in ascending order.


To change this behavior and place NULL values at the beginning:


SELECT column1


FROM table_name


ORDER BY column1 ASC NULLS FIRST;


Important Notes: To know more about Oracle Queries, Please go through the below youtube video links:-----------

Topics that are covered in Videos: Visit Oracle Database tutorial


Oracle SQL Query Part 1


Oracle SQL Query part 2


Oracle Dual table and Alias Column


Oracle fetch clause, Oracle in and not in operator


Oracle between, Oracle Like Operator


Oracle IS NULL operator, , Oracle Joins (inner, left, right and full outer join)


Oracle Cross Join, Oracle self join


Oracle UNION, Oracle intersect, Oracle minus


Oracle Subquery, Oracle corelated subquery with exists operator


Oracle exists update stmt, ,Oracle Any operator


Oracle All operator, view creation, Oracle Rollup


Oracle PIVOT clause, Oracle UNPIVOT


Oracle INSERT , Oracle INSERT INTO SELECT


Oracle Update, Oracle Delete


Oracle MERGE statement


UnConditional Oracle INSERT ALL statement, Conditional Oracle INSERT ALL statement


Oracle CASE Expression


Conclusion


The ORDER BY clause is a fundamental feature in Oracle SQL that helps you organize and present data effectively.


By understanding its usage and applying it with real-time examples, beginners can master sorting techniques and enhance their SQL skills.


From basic sorting to handling multiple columns and date sorting, ORDER BY offers versatility to meet various sorting requirements.


By practicing with different scenarios and experimenting with the ORDER BY clause, you'll gain confidence in sorting data and making your queries more informative and user-friendly.