# Expressions on LONGs

Derby 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.
Parent topic: Derby and standards
Related concepts
Dynamic SQL
Cursors
Information schema
Transactions
Stored routines and PSM
Calling functions and procedures
Unique constraints and nulls
NOT NULL characteristic
DECIMAL max precision
CLOB and BLOB
ALTER TABLE