In LINQ to SQL, a Join clause with an into expression is called a Group join. In LINQ to SQL, the Group join produces a sequence of object elements based on the matching elements from both collections.
Following is the syntax of using LINQ to SQL Group Join to get data from multiple tables.
If you observe the above syntax, we joined “EmployeeDetails”, “Departments” tables to get required data by using group join.
Before we start implementing the LINQ to SQL group join example first, we need to create a database with required tables and map those tables to LINQ to SQL file (.dbml). If you don't know the process, don't worry; check this link create and map database tables to LINQ to SQL file (.dbml).
Once we create and map required tables to the .dbml file now, we will show data in our application for that Right-click on the application à select Add à New Item à Select Web Form à Give name as Default.aspx and click OK button.
Now open the Default.aspx page and write the code as shown below.
Now open the code behind file and write the code as shown below.
If you observe the above example, we are trying to get data from the “EmployeeDetails” and “Departments” table using Group join.
Following is the result of the LINQ to SQL group join example.
This is how we can use LINQ to SQL Group join in c# to get the required data from multiple tables based on our requirements.