Specificaly to the problem you are adressing regarding the UPDATE query. It is not making sense why, as you stated already. Have you tried using the query builder and adding
to the criteria field? What does the SQL look like using the query builder?
The other issue is that you are updating a field in a table based on a calculation. So I will comment on that point. It is not associated with the problem you are posting about but, it is generaly not a good idea to store calculated data. So something like the third option I offered earlier should be considered.
You could create a select query based on the table Orders. Create an alias that has an IIf. So you would create a new column by entering the following in a blank field.
Code:
MyNewAlias: IIf([Order].[PRICE_USD] > 9999.99, "Check- Value over 10K USD", "Acceptable")
You need to verify the data type of Price_USD