小编lou*_*lau的帖子

我是 postgresql 新手。谁能建议这个错误的原因和解决方案？但是，如果我选择额外的总和（s.length），它会起作用，但我不会在结果中这样做。

代码：

create or replace view q1("group",album,year)
as
select g.name, a.title, a.year
from Groups g, Albums a, Songs s
where a.made_by = g.id and s.on_album = a.id
group by a.title, g.name, a.year
order by sum(s.length) desc 
limit 1
;

错误信息：

错误：无法从视图中删除列

我正在尝试从 werkzeug.utils 导入 secure_filename 并且它发出错误。它在我的基本虚拟环境下运行良好。

代码：

# Flask packages
from flask import Flask, render_template, request, session, redirect, flash, send_file
from flask_bootstrap import Bootstrap 
from flask_uploads import UploadSet,configure_uploads,IMAGES,DATA,ALL

# Systems
import os 
import sys
import json
from werkzeug.utils import secure_filename

错误：

    (absa_annotation) C02QM3FSFVH3:ABSA-annotation-tool kwunkeilau$ python3 app.py 
Traceback (most recent call last):
  File "app.py", line 4, in <module>
    from flask_uploads import UploadSet,configure_uploads,IMAGES,DATA,ALL
  File "/Users/kwunkeilau/anaconda3/envs/absa_annotation/lib/python3.7/site-packages/flask_uploads.py", line 26, in <module>
    from werkzeug import secure_filename, FileStorage
ImportError: cannot import name 'secure_filename' from 'werkzeug' (/Users/kwunkeilau/anaconda3/envs/absa_annotation/lib/python3.7/site-packages/werkzeug/__init__.py)