Add a blank value to a Power Apps dropdown control

Add a blank row to a table in Power Apps. This is usefull for adding a blank row to a dropdown or combobox.

Add the following code snippet to the items property of a dropdown or combobox control. The dropdown options will contain the distinct values of the sharepoint column and a blank value at the top. This technique can be used to add any additional value e.g. 'All' or 'Other'.

Ungroup(
    Table(
        {MyTable: Table({Value: Blank()})},
        {
             MyTable: SortByColumns(
                Distinct(
                    'SharePointList',
                    'SharePointColumn'
                ),
                "Value"
            )
        }
    ),
    MyTable
)