combine 2 data sources and display data on single table in power apps

• work environment : power apps

• data source : employee table and department table in sql server.

• the problem scenario : please, have a look on the diagram :

as per the diagram I want to display a table on the simple canvas app which is a combined result of both employee and department table.

I have no idea how I could do that in power apps. tried many things maybe I am doing it in an incorrect way.

App > On Start:

ClearCollect(NewTable,
    AddColumns(Employee_Table,
        "Department_Name",LookUp(Department_Table,Department_ID=Employee_Table[@Department_ID],Department_Name)))

Then set the table's item to NewTable.