oracle 8.1 "expression must have same datatype as corresponding expression"

I have been developing for Oracle 9i a bit, and there I can do a select like this:

SELECT F1, F2, NumField
FROM TBL1 UNION SELECT F1, F2, NULL AS NumField
FROM TBL2 This query doesn't make much sense, but it illustrates my problem. As I said, it works in 9i, but in 8.1, I get the "expression must have same datatype as corresponding expression" error. NumField is a numeric field, and it can be any number, so I can't just make up a number for the field in the second part of the UNION. In queries where the "real" field is a string, the made up filed can be NULL. I hope this makes sense to someone. Any idea how I can accomplish this in Oracle 8i?

Thanks in advance,

TK Received on Tue May 09 2006 - 19:51:17 CDT