SQL queries that use EXISTS subqueries are inefficient because the subquery is re-run for every row in the outer query’s table. There
are more efficient ways to write most queries, ways that do not use the EXISTS condition.
Noncompliant code example
SELECT name
FROM employee
WHERE EXISTS (SELECT * FROM department WHERE department_id = id AND name = 'Marketing');
Compliant solution
SELECT name
FROM employee INNER JOIN department AS d
ON department_id = d.id AND d.name = 'Marketing';
