[Sqlalchemy-tickets] Issue #4174: Parenthesis Ignored (zzzeek/sqlalchemy)

[Lukas S. <iss...@bi...>]

New issue 4174: Parenthesis Ignored
https://bitbucket.org/zzzeek/sqlalchemy/issues/4174/parenthesis-ignored

Lukas Siemon:

Minimal Test Case below (uses postgresql 9.6 latest).

Generates SQL (which is obviously invalid):
```sql
SELECT
  now() + CAST(%(param_1)s AS INTERVAL) at time zone %(param_2)s AS anon_1, 
  person.id AS person_id
FROM
  person
```

We are solving this for now by casting explicitly to DateTime, but we would expect parenthesis to be handled correctly.


```python
import unittest
from sqlalchemy import Column, Integer, func
from sqlalchemy.dialects.postgresql import INTERVAL
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import column_property
from flask import Flask
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = (
    "postgresql://postgres:password@localhost:5432/gitl_tmp")
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
db = SQLAlchemy(app)

Base = declarative_base()


class Person(db.Model):
    __tablename__ = 'person'
    id = Column(Integer, primary_key=True, nullable=False)
    time = column_property(
        (
            func.now() +
            func.cast('1 week', INTERVAL)
        ).op("at time zone")('America/Vancouver')
    )


db.drop_all()
db.create_all()


class TestExecutionOrder(unittest.TestCase):

    def test_execution_order(self):

        db.session.add(Person())
        db.session.commit()

        query = Person.query
        print query
        person = Person.query.one()
        print person.time
```