Sub-Query or Left-Outer Join (Performance Wise)

Which one is Better and why ?
Use SQL subselects to consolidate queries on multiple tables into a single statement
Or
Use Left Outer Join
Example:
Table Employee(Employee_ID,Employee_Name,Department_ID)
Table Department(Department_ID,Department_Name)
· Table Employee has million records, table Department has Few Records
· Some Of the employees does not have department
Which Query is better for performance? SelectEmployee_ID,Employee_Name, (Select Department_Name From Department Where Department .Department_ID = Employee. Department_ID) as Department_NameFrom Employee OR Select Employee_ID,Employee_Name, Department_Name From EmployeeLeft Outer JoinDepartmentOn Department .Department_ID = Employee. Department_ID

Check the execution plans that SQL generates for the queries. If they are identical, it doesn't matter which of the two versions you use.

I prefer joins over subqueries. The SQL optimizer can sometimes transform a subquery into a join, but not always. Plus, I think the join more clearly communicates what you're trying to do.