permits expressions on LONG VARCHAR; however LONG VARCHAR data types are not allowed in the following clauses, operations, constraints, functions, and predicates.

• GROUP BY clauses
• ORDER BY clauses
• JOIN operations
• PRIMARY KEY constraints
• Foreign KEY constraints
• UNIQUE key constraints
• MIN aggregate function
• MAX aggregate function
• [NOT] IN predicate
• UNION, INTERSECT, and EXCEPT operators

SQL99 also places some restrictions on expressions on LONG types.