python - 如何调试 cursor.execute (psycopg2) is NoneType

Question

我尝试对我的 postgres 数据库运行 SQL，

我通过的连接对象

import psycopg2
conn_string = "host='localhost' port='5432' dbname='postgres' user='postgres' password='mysecretpassword'"
conn = psycopg2.connect(conn_string)

好像还可以

result = cursor.execute(
"""
select 
* 
from 
planet_osm_point limit 10
""")

结果是 Nonetype，所以一定是有问题吗？

我做错了什么？我该如何调试它？

Answer 1

cursor.execute() 只执行查询，不获取任何数据。为了接收数据，您需要调用 cursor.fetchall() 或 cursor.fetchone()。

import psycopg2
conn_string = "host = 'localhost' port = '5432' dbname = 'postgres' user = 'postgres' password = 'mysecretpassword'"
conn = psycopg2.connect(conn_string)
cursor.execute(
""" 
select 
* 
from 
planet_osm_point limit 10
""")

result = cursor.fetchall()