Python psycopg2 syntax error

Question

I am new to python and working on using the psycopg2 to insert data in postgres database. I am trying to insert items but get the error message

"Psycopg2.ProgrammingError: syntax error at or near "cup" LINE 1: INSERT INTO store VALUES(7,10.5,coffee cup)

with the ^ next to coffee cup. I am assuming the order is wrong but i thought you could enter it this way as long as you specified the values.

Here is the code.

import psycopg2

def create_table():
    conn=psycopg2.connect("dbname='db1' user='postgres' password='postgress123' host='localhost' port='5432'")
    cur=conn.cursor()
    cur.execute("CREATE TABLE IF NOT EXISTS store (item TEXT, quantity INTEGER, price REAL)")
    conn.commit()
    conn.close()

def insert(quantity, price, item):
    conn=psycopg2.connect("dbname='db1' user='postgres' password='postgress123' host='localhost' port='5432'")
    cur=conn.cursor()
    cur.execute("INSERT INTO store VALUES(%s,%s,%s)" % (quantity, price, item))
    conn.commit()
    conn.close()

create_table()
insert(7, 10.5, 'coffee cup')

Answer 1

Remember to always use the second argument of the execute command to pass the variables, as stated here.

Also, use the name of the fields in your syntax:

cur.execute("INSERT INTO store (item, quantity, price) VALUES (%s, %s, %s);", (item, quantity, price))

That should do the trick.

Answer 2

Problem in your case is coffee cup parameter value is considered as string but psycopg2 accept the value in single quote. Basically as per my understanding when we create SQL query for psycopg2 it ask for single quote for data parameters [if you have given double quote for query start and end] In your case you have given double quote for Query Start and end so you need to give single quote for the parameters.

---

My Observation is you provide single quote for each data paramater in psycopg2

---

import psycopg2

def create_table():
    conn=psycopg2.connect("dbname='db1' user='postgres' password='postgress123' host='localhost' port='5432'")
    cur=conn.cursor()
    cur.execute("CREATE TABLE IF NOT EXISTS store (item TEXT, quantity INTEGER, price REAL)")
    conn.commit()
    conn.close()

def insert(quantity, price, item):
    conn=psycopg2.connect("dbname='db1' user='postgres' password='postgress123' host='localhost' port='5432'")
    cur=conn.cursor()
    #cur.execute("INSERT INTO store VALUES(%s,%s,%s)" % (quantity, price, item))
    cur.execute("INSERT INTO store VALUES('%s','%s','%s')" % (quantity, price, item))
    conn.commit()
    conn.close()

create_table()
insert(7, 10.5, 'coffee cup')