EXISTS Operator
The logical operator EXISTS is used to check if a subquery is returning any rows. It returns true if the subquery returns one or more rows; otherwise, it returns false. Instead of the IN operator that matches values directly, the EXISTS checks only the presence of rows returned by the correlated or non-correlated subquery.
Syntax:
SELECT column_name(s)
FROM table_name
WHERE EXISTS (subquery);
Difference Between EXISTS and IN in SQL Server?
The SQL Server database developer is quite familiar with the filtering and retrieving operators which enable the developer to execute the query rapidly. When it comes to these operators namely IN and EXISTS, they share almost similar purposes but work differently at the same level.
Understanding the variations between the two operators is very important for better tuning of query performance and the desired outcomes.