Sql select distinct multiple columns

Problem:

You’d like to query your data to return the result without duplicate rows. Imagine you have a table with repeated entries, and you only want each unique entry to show up once. This helps in getting a cleaner and more concise set of results, making analysis easier.

Example:

Our database has a table named with data in the columns , , and .

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You’d like to get a list of unique first and last names of the authors.

author_firstname	author_lastname	book_title
George	Orwell	Animal Farm
Dan	Brown	The Davinci Code
George	Orwell	1984
Daniel	Silva	The Order
Franz	Kafka	The Metamorphosis

Solution:

We’ll use the SQL clause to remove duplicate rows.

Here’s the query:

SELECT DISTINCT author_firstname, author_lastname FROM books;

Here’s the result of the query:

author_firstname	author_lastname
George	Orwell
Dan	Brown
Daniel	Silva
Franz	Kafka

Discussion:

The clause is used in the statement to filter out duplicate rows in the result set.

You can use when you select a single column, or when you select multiple columns as w

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