无法在 Python 3.9.2 中导入模块 qgis

Question

I'm working on Python 3.9.2 and got this

error:No module named qgis

I'm trying to connect to a database and query within it. I've seen the code beLow working under python 2. Is there any difference with Python 3?

[...]
from qgis.core import *
import qgis.utils


uri.setConnection('{0}'.format(hote_IP), "5432", '{0}'.format(xxx), '{0}'.format(xxx),'{0}'.format(xxx))    
db = QSqlDatabase.addDatabase("QPSQL")    
db.setHostName(uri.host())    
db.setDatabaseName(uri.database())    
db.setPort(int(uri.port()))    
db.setUserName(uri.username())    
db.setPassword(uri.password())

sql = '''select field1, field2 from schema.table'''    
query = db.exec_(sql)
print(str(query.value(0))

Answer 1

Try to install it again via python 3:

python3 -m pip install qgis

Answer 2

I have had the same problem when creating virtual environments for python projects and then trying to import QGIS. It is quite complicated to install QGIS in a virtual environment. What I do to solve this is to create venvs that have access to the system level site packages where QGIS lives after install. I use the following:

python3 -m venv myvenv --system-site-packages

The prerequisite for this to work, however, is that you have properly install QGIS and can access that from your system level python interpreter. I use Ubuntu and the instructions properly installing QGIS on Ubuntu are here .