Zhenjie Fu wrote: Do I have to create a lot of temp tables? Nope, only for the two tables that you're importing with the OpenRowSet-command. Zhenjie Fu wrote: Is it a bug or some mis-understand by me? It's an error in one of the imports. Hence the suggestion to select those two first into a temporary table, and then to union on those. Bastard Programmer from Hell :suss: