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我学习的SQLAlchemy的表达式语言,和我试图执行返回通过select([users.c.id, users.c.id])
单一重复列一个简单的查询:如何强制SQLAlchemy包含重复列?
from sqlalchemy import create_engine, Table, Column, Integer, String, MetaData, insert, select
engine = create_engine('sqlite:///:memory:', echo=True)
conn = engine.connect()
metadata = MetaData()
users = Table('users', metadata,
Column('id', Integer, primary_key=True),
Column('name', String),
Column('fullname', String),
)
metadata.create_all(engine)
conn.execute(users.insert(), [
{'id': 1, 'name' : 'jack', 'fullname': 'Jack Jones'},
{'id': 2, 'name' : 'wendy', 'fullname': 'Wendy Williams'},
])
print(list(conn.execute(select([users.c.id, users.c.id]))))
,输出:
[(1,), (2,)]
即仅两个请求的列之一。我预计:
[(1, 2), (2, 2)]
要仔细检查了我的预期是正确的,我直接在sqlite3的跑的等效查询和PostgreSQL 9.2([1],[2]下面),两者都正确返回重复的IDS 。我正在使用SQLAlchemy版本0.8.0b2,Python 3.2.3,sqlite3 3.6.12和Mac OS X 10.6和10.7。
在此先感谢!
[1] SQLITE3
$ sqlite3 temp.db
CREATE TABLE users(id INTEGER, name TEXT, fullname TEXT);
INSERT INTO users VALUES(1, 'jack', 'Jack Jones');
INSERT INTO users VALUES(2, 'wendy', 'Wendy Williams');
SELECT id, id FROM users;
->
1|1
2|2
[2]的PostgreSQL
$ /Library/PostgreSQL/9.2/bin/psql -U postgres
CREATE DATABASE temp;
CREATE TABLE users(id INTEGER, name TEXT, fullname TEXT);
INSERT INTO users VALUES(1, 'jack', 'Jack Jones');
INSERT INTO users VALUES(2, 'wendy', 'Wendy Williams');
SELECT id, id FROM users;
->
1 | 1
2 | 2