python pyscopg2 无法从 AWS redshift 中选择数据

Question

我在 AWS redshift 上有一个 postgres 数据库。目前我使用 Python Pyscopg2 与数据库进行交互。我发现我可以跑了：

curosr.execute("INSERT INTO datatype VALUES (%s, %s)", ("humidity", "some description"))
connect.commit()

但是当我这样做时：

for row in cursor.execute("SELECT * FROM datatype"):
    print(row)

无论我做什么，它总是返回我 None 类型。 任何人都可以给我建议，什么是与 redshift postgres 交互的正确方法？

谢谢

根据需要，这是完整代码

##encoding=utf8

from __future__ import print_function
import psycopg2

def connect():
    conn = psycopg2.connect(host = "wbh1.cqdmrqjbi4nz.us-east-1.redshift.amazonaws.com",
                            port = 5439,
                            dbname = "dbname",
                            user = "user",
                            password = "password")
    c = conn.cursor()
    return conn, c

conn, c = connect()

c.execute("INSERT INTO table netatmo VALUES (%s, %s)", (1, 10.5))
conn.commit() # this works, and I can see the data in other db client software

for row in c.execute("SELECT * FROM netatmo").fetchall(): # this not working
    print(row) # AttributeError: 'NoneType' object has no attribute 'fetchall'

Answer 1

你错过了“fetchall()”， 更新时-您不需要它，但是选择时-您必须获取结果 http://initd.org/psycopg/docs/cursor.html

您的代码应如下所示：

cursor.execute("SELECT * FROM datatype;")
for row in cursor.fetchall():
    print(row)