在 python postgresql 中的参数化插入查询中出现语法错误

Question

I am trying to send data to PostgreSQL, data is a tuple of strings ie (time, price).

The problem is when I send data using a simple query ( not parametrized ) it works fine. Following is the simple query working perfectly.

cur.execute("INSERT INTO paxos (date,price) VALUES ('2020-04-09 14:39:58.145804', '$1,664.08');");

But as those values aren't fixed, so I want to store them in variable and use a parameterized query for sending data, but the parameterized query isn't working for me. Here is the parameterized query.

cur.execute("INSERT INTO paxos (date, price) values (?, ?)",(time, price))

Here is the complete function I am trying to implement:

def insert_data(time, price):

con = psycopg2.connect(database="", user="", password="", host="", port="5432")
print("Database opened successfully")
cur = con.cursor()

data_tuple = (time, price)

cur.execute("insert into paxos (date, price) values (?, ?)",(time, price))

con.commit()
print("Record inserted successfully")
con.close()
insert_data("2020-04-09 14:39:58.145804", "$1,664.08")

Here is the error message:

Answer 1

It seems like this is a python syntax error. I think you should use the format method of the string object (see codesnippet below). I can't test it right now, but according to some old code of mine, I always "built" a query string first and then passed the string object to the cursor. Try something like that:

artist = "Aphex Twin"
title = "Windowlicker"    
query = '''SELECT EXISTS(SELECT * FROM tracks
                    WHERE artist ILIKE \'{}\'AND
                    title ILIKE \'{}\')'''.format(artist, title)
cursor.execute(query)