SQL Subqueries Correlated Subqueries
Example
Correlated (also known as Synchronized or Coordinated) Subqueries are nested queries that make references to the current row of their outer query:
SELECT EmployeeId
FROM Employee AS eOuter
WHERE Salary > (
SELECT AVG(Salary)
FROM Employee eInner
WHERE eInner.DepartmentId = eOuter.DepartmentId
)
Subquery SELECT AVG(Salary) ... is correlated because it refers to Employee row eOuter from its outer query.
