I have 3 tables Employee,Project and Assignment. An employee can be assigned to multiple projects and one project can have multiple employees. Assignment table keeps many to many relationship between employees and projects. I want a sql query in sql server that returns a list of employees that have ever worked on more than one project at the same time.
Structure of tables
ProjName, ProjStartDate, ProjEndDate
AssignmentId, ProjId, EmpId, AssStartDate, AssEndDate