WHERE NOT ...

Maybe this quesion will seem trivial for some database experts, but I cannot find an easy and clean solution, so I ask it.

Suppose you have a table T with 3 fields A, B and C and you've got an index to all these fields.
I have noticed that when you make some query like

SELECT A,B,C
FROM T
WHERE A ="" AND
               B >"first"
ORDER BY B,C It runs quickly, because of the index. But if in the WHERE line you write A<>"" instead of A="", the negated condition makes the query very slow.
Right now, I run this query over an Access 97 database, but in the future it will run in Oracle 7.

The question is: is there an easy way to write this query (maybe changing the index, or something like that) in order to make it fast, even in Access?
If not, is there a solution in Oracle 7?

Thank you. Received on Fri Jul 03 1998 - 03:20:50 CDT