Thanks, Dave!! My bad - I didn't read it carefully enough!

I got this error message:

Msg 4108, Level 15, State 1, Line 3

Windowed functions can only appear in the SELECT or ORDER BY clauses.

when running the following codes:

select * ,row_number() over...

I have been troubled by identifying the error rows in the MERGE process so thanks for sharing this.

What if there are millions of rows to merge ... will this affect...

Great question! Learned something new again!

Is it the same for connecting from Excel to SSAS cubes?

You can only use windows authentication to connect Excel to SSAS cube?

Thanx!

Can you use a default value to show it is an non-existing record? Like 'N/a' or a "-1' key?