How to use NOT EXISTS Clause In SQL
In the following query, we first select only those records in the inner query that are present in both the tables by comparing the name in the WHERE clause. Later we discard these records from the professor table by utilising the NOT EXISTS clause.
SELECT * FROM professor
WHERE NOT EXISTS
(
SELECT * FROM hod
WHERE professor.name=hod.name
);
Output:
Explanation: This above query selects all records from the “professor” table where there is no corresponding record in the “hod” table with the same name.
How to Select Rows that Don’t Exist in Other Table in PostgreSQL?
In PostgreSQL, there are times when we need to find records in one table that do not exist in another table. This can be useful for various data manipulation tasks and ensuring data integrity.
In this article, we will explore different approaches along with examples to achieve this using PostgreSQL. By the end, you will have a clear understanding of how to efficiently select rows that don’t exist in another table which help to improve your data management skills in PostgreSQL.