What is

in SQL Server?**Cross Join**

Updated on October 28, 2014
VIKRAM
677

__CROSS JOIN:__

A cross join that does not have a WHERE clause produces the Cartesian product of the tables involved in the join. The size of a Cartesian product result set is the number of rows in the first table multiplied by the number of rows in the second table. The following example shows a Transact-SQL cross join.

**Example:**

select E.EmployeeID, E.EmployeeName, E.Email, E.DepartmentID, D.DepartmentName from Employee E cross join Department D

The result set contains 15 rows (Employee has 3 rows and Department has 5; 3 multiplied by 5 equals 15).

**Note:**

However, if a WHERE clause is added, the cross join behaves as an inner join. For example, the following Transact-SQL queries produce the same result set.

select E.EmployeeID, E.EmployeeName, E.Email, E.DepartmentID, D.DepartmentName from Employee E cross join Department D where E.DepartmentID = D.DepartmentID

**(or)**

select E.EmployeeID, E.EmployeeName, E.Email, E.DepartmentID, D.DepartmentName from Employee E inner join Department D on E.DepartmentID = D.DepartmentID

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