In Power Query, how do you combine Columns 1 and 2 to produce Column 3 as in the example below. The value 999999999 is stored as text.
<colgroup><col><col><col></colgroup><tbody>
</tbody>
Col1 | Col2 | Col3 |
999999999 | 999999999 | 999999999 |
null | #N/A | null |
999999999 | #N/A | 999999999 |
null | 999999999 | 999999999 |
<colgroup><col><col><col></colgroup><tbody>
</tbody>