How to use the EXISTS Clause In SQL
The technique applies EXISTS condition as part of the column select statement and conditions are defined for a given row check. This will result in one when at least one row is found to match the criteria or 0 when there is no matching row.
SELECT exists(SELECT 1 FROM users WHERE username = 'john_doe') AS row_exists;
Output:
Explanation: A row of internal function “EXISTS” displays and gives the value 1 if a row with the username ‘john_doe’ exists in the users table. If in the absence of any line of code that returns 0 is executed.
How to Check if a Row Already Exists in SQLite?
SQLite is a widely used relational database management system due to its simplicity, lightweight design and energy efficiency features.
When working with SQLite databases, It is very important to ensure data integrity therefore it is necessary to avoid accidentally inserting duplicated records.
In this article, we will be unraveling some of the ways to overcome this obstacle using SQLite.