# sqlalchemy.exc.ProgrammingError: (psycopg2.errors.UndefinedFunction) operator does not exist: character varying = integer

- **ID:** `python/sqlalchemy-invalid-operator-for-type`
- **Domain:** python
- **Category:** type_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

Comparing a string column with an integer value in a query without proper type casting.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 3.x | active | — | — |

## Workarounds

1. **** (90% success)
   ```
   from sqlalchemy import cast, Integer
result = session.query(User).filter(cast(User.age, Integer) == 25).all()
   ```
2. **** (95% success)
   ```
   class User(Base):
    __tablename__ = 'users'
    age = Column(Integer)  # not String
   ```

## Dead Ends

- **** — If the column is string and you pass string, it may work, but can cause implicit casts and performance issues; not robust. (40% fail)
- **** — Data inconsistency leads to runtime failures. (80% fail)