EXCEPT keyword in Oracle

Oracle MINUS is an operator; it's equivalent to EXCEPT in SQL Server. Here is a previous post explaining the difference. Here's a trivial example:

SELECT a, b, c
FROM   table_a
MINUS
SELECT a, b, c
FROM   table_b

If you still have problems, add the complete query you are using to your question; it's likely a simple syntax error.

Oracle 20c will support EXCEPT/EXCEPT ALL keywords.

SELECT col1, col2
FROM t1
EXCEPT
SELECT col1, col2
FROM t2;

or EXCEPT ALL if you want to handle duplicates:

SELECT col1, col2
FROM t1
EXCEPT ALL
SELECT col1, col2
FROM t2;

4.6 Set Operators

Set operators combine the results of two component queries into a single result.

EXCEPT All distinct rows selected by the first query but not the second

EXCEPT ALL All rows selected by the first query but not the second including duplicates