我正在编写一个活动仪表板，我正在努力加入表格以建立层次关系，这样我就可以获得最新的活动。除了下面的group_concat函数之外，我能够从数据库中获取查询。 （我包括AutoEscalationDB类供参考，因为这是类中所有函数访问现有数据库的方式。该类中的其他代码被编辑，但它与此问题无关。）< / p>
from app import app
from sqlalchemy import create_engine, or_, func
from sqlalchemy import *
from sqlalchemy.sql import expression
from sqlalchemy.orm import scoped_session, aliased, sessionmaker, relationship
from sqlalchemy.types import TIMESTAMP, INTEGER
from sqlalchemy.ext.automap import automap_base
from sqlalchemy.orm.exc import FlushError
from sqlalchemy.exc import InvalidRequestError
from sqlalchemy.ext import compiler
from sqlalchemy.sql import ColumnElement
from sqlalchemy.sql.expression import FunctionElement, ClauseElement
class event_id(ColumnElement):
type = INTEGER()
class group_concat(ColumnElement):
def __init__(self, col1, col2, separator):
self.col1 = col1
self.col2 = col2
self.type = col1.type
self.separator = separator
separator = "','"
class AutoEscalationDB(object):
def __init__(self, host=app.config['MYSQL_DATABASE_HOST'],
port=app.config['MYSQL_DATABASE_PORT'],
user=app.config['MYSQL_DATABASE_USER'],
passwd=app.config['MYSQL_DATABASE_PASSWORD'],
db=app.config['MYSQL_DATABASE_DB'],
short_retry=5, lifetime_retry=25,
socket=app.config['MYSQL_DATABASE_SOCKET']):
self.URI = 'mysql://%s:%s@%s:%s/%s?unix_socket=%s' %(user, passwd, host, port, db, socket)
self.create_model()
session_factory = sessionmaker(bind=self.engine)
self.session = scoped_session(session_factory)
self.methods = {
1: self.Emails,
2: self.Phones,
}
@compiler.compiles(group_concat, 'mysql')
def compile_group_concat(element, compiler, **kw):
return "GROUP_CONCAT(%s ORDER BY %s SEPARATOR %s)" % (
compiler.process(element.col1),
compiler.process(element.col2),
separator
)
def get_escalations(self, event_id=None, **kwargs):
es1 = aliased(self.Event_statuses)
es2 = aliased(self.Event_statuses)
e1 = aliased(self.Events)
e2 = aliased(self.Events)
m = MetaData()
separator = "','"
t = Table('e2', m, Column('event_id', Integer), Column('event_id', Integer))
eid = group_concat(t.c.event_id, t.c.event_id, ',').compile(bind=create_engine('mysql://'))
query = self.session.query(e1).\
from_self(e1.parent_event_id,
e1.event_id,
es1.event_status,
e1.event_name,
eid.string,
e1.reporter,
e1.message,
self.Users.user_id,
self.Users.username,
self.Users.first_name,
self.Users.last_name,
e1.timestamp
).outerjoin(e2, e2.parent_event_id == e1.event_id).\
join(es1, es1.event_statuses_id == e1.event_status_id).\
outerjoin(es2, e2.event_status_id == es2.event_statuses_id).\
outerjoin(self.Users, self.Users.user_id == e1.user_id)
results = {}
for row in query:
row = row._asdict()
if row['event_status'] in results.keys():
results[row['event_status']].append(row)
else:
results[row['event_status']] = [row]
return True, results
当我点击网址时出现此错误：
OperationalError: (_mysql_exceptions.OperationalError) (1054, "Unknown
column 'e2.event_id' in 'field list'") [SQL: u"SELECT
anon_1.events_1_parent_event_id AS anon_1_events_1_parent_event_id,
anon_1.events_1_event_id AS anon_1_events_1_event_id,
event_statuses_1.event_status AS event_statuses_1_event_status,
anon_1.events_1_event_name AS anon_1_events_1_event_name,
GROUP_CONCAT(e2.event_id ORDER BY e2.event_id SEPARATOR ','),
anon_1.events_1_reporter AS anon_1_events_1_reporter,
anon_1.events_1_message AS anon_1_events_1_message, users.user_id AS
users_user_id, users.username AS users_username, users.first_name AS
users_first_name, users.last_name AS users_last_name,
anon_1.events_1_timestamp AS anon_1_events_1_timestamp \nFROM (SELECT
events_1.event_id AS events_1_event_id, events_1.event_type_id AS
events_1_event_type_id, events_1.reporter AS events_1_reporter,
events_1.parent_event_id AS events_1_parent_event_id,
events_1.property_id AS events_1_property_id, events_1.event_name AS
events_1_event_name, events_1.event_status_id AS
events_1_event_status_id, events_1.escalation_type_id AS
events_1_escalation_type_id, events_1.timestamp AS events_1_timestamp,
events_1.user_id AS events_1_user_id, events_1.message AS
events_1_message, events_1.group_id AS events_1_group_id,
events_1.shift_id AS events_1_shift_id \nFROM events AS events_1) AS
anon_1 LEFT OUTER JOIN events AS events_2 ON events_2.parent_event_id =
anon_1.events_1_event_id INNER JOIN event_statuses AS event_statuses_1 ON
event_statuses_1.event_statuses_id = anon_1.events_1_event_status_id LEFT
OUTER JOIN event_statuses AS event_statuses_2 ON events_2.event_status_id
= event_statuses_2.event_statuses_id LEFT OUTER JOIN users ON
users.user_id = anon_1.events_1_user_id"]
如果我注释掉eid.string，它会按原样返回查询：
SELECT anon_1.events_1_parent_event_id AS
anon_1_events_1_parent_event_id, anon_1.events_1_event_id AS
anon_1_events_1_event_id, event_statuses_1.event_status AS
event_statuses_1_event_status, anon_1.events_1_event_name AS
anon_1_events_1_event_name, anon_1.events_1_reporter AS
anon_1_events_1_reporter, anon_1.events_1_message AS
anon_1_events_1_message, users.user_id AS users_user_id, users.username
AS users_username, users.first_name AS users_first_name, users.last_name
AS users_last_name, anon_1.events_1_timestamp AS
anon_1_events_1_timestamp
FROM (SELECT events_1.event_id AS events_1_event_id,
events_1.event_type_id AS events_1_event_type_id, events_1.reporter AS
events_1_reporter, events_1.parent_event_id AS events_1_parent_event_id,
events_1.property_id AS events_1_property_id, events_1.event_name AS
events_1_event_name, events_1.event_status_id AS
events_1_event_status_id, events_1.escalation_type_id AS
events_1_escalation_type_id, events_1.timestamp AS events_1_timestamp,
events_1.user_id AS events_1_user_id, events_1.message AS
events_1_message, events_1.group_id AS events_1_group_id,
events_1.shift_id AS events_1_shift_id
FROM events AS events_1) AS anon_1 LEFT OUTER JOIN events AS events_2 ON
events_2.parent_event_id = anon_1.events_1_event_id JOIN event_statuses
AS event_statuses_1 ON event_statuses_1.event_statuses_id =
anon_1.events_1_event_status_id LEFT OUTER JOIN event_statuses AS
event_statuses_2 ON events_2.event_status_id =
event_statuses_2.event_statuses_id LEFT OUTER JOIN users ON users.user_id = anon_1.events_1_user_id
如果我坚持使用＆＃39; print eid＆＃39;声明，它返回这个，应该是正确的：
GROUP_CONCAT(e2.event_id ORDER BY e2.event_id SEPARATOR ',')
我尝试复制的SQL查询是：
SELECT
e1.parent_event_id,
e1.event_id,
es1.event_status,
e1.event_name,
GROUP_CONCAT(e2.event_id ORDER BY e2.event_id SEPARATOR ', ') AS child_events,
e1.reporter,
e1.message,
u1.user_id,
u1.username,
u1.first_name,
u1.last_name,
e1.timestamp
FROM events e1
LEFT JOIN events e2 ON (e2.parent_event_id = e1.event_id)
JOIN event_statuses es1 ON (es1.event_statuses_id = e1.event_status_id)
LEFT JOIN event_statuses es2 ON (es2.event_statuses_id = e2.event_status_id)
LEFT JOIN users u1 ON (u1.user_id = e1.user_id);
我已确认查询本身有效。
我怀疑这部分是group_concat语句：
.compile(bind=create_engine('mysql://'))
正在创建一个新的mysql引擎，而不是绑定到现有数据库，因此无法从Events表中找到event_id列。不幸的是，这不是我的代码，而且我是sqlalchemy的新手，所以我在黑暗中进行拍摄。任何建议都是最受欢迎的，因为我已经在这里停顿了几天而且我被困住了。提前谢谢！