SELECT d. Name AS 'Department', e1.Name AS 'Employee', e1. Salary FROM Employee e1 JOIN Department d ON e1. DepartmentId . Id WHERE SELECT COUNT (DISTINCT e2. Salary) FROM Employee e2 WHERE e1. Salary AND e1.DepartmentId e2. DepartmentId

This is leetcode number 185.

Could you please provide a detailed explanation about what the sql codes after the WHERE clause is doing?

Sol14:

The SQL code after the WHERE clause is a subquery, which is used to find the number of employees in the same department as e1 whose salaries are greater than e1's salary. The outer query then filters the results to only include employees where this count is less than 3.

To break it down further, here's what's happening step by step:

1. The subquery SELECT COUNT(DISTINCT e2.Salary) FROM Employee e2 WHERE e1.Salary is used to find the number of distinct salaries (excluding e1's salary) that are greater than e1's salary, but only for employees who work in the same department as e1.

2. This subquery is used in the outer query's WHERE clause, where 3 > is used to filter the results to only include employees where the count of salaries greater than e1's salary is less than 3.

So essentially, the overall query is looking for employees who have fewer than three colleagues in the same department with a higher salary than they do.