Sql query with variables (real or integer) - select

Question

I'm learning python... I tried to execute sql queries with parameters without success...
I tried:
from tkinter import*
import tkinter as tk
from tkinter import ttk
import sqlite3
realNumber = 2.0
database = sqlite3.connect('NumDB.db')
cursor = database.cursor()
cursor.execute("SELECT numColumn from numTable WHERE realNumber=?", ( realNumber ))
results = cursor.fetchall()
print(results)
cursor.close()
database.close()
it works when I define the variable as text:
realNumber "2.0"
or
cursor.execute("SELECT numColumn from numTable WHERE realNumber=?", ( str(realNumber)))
the type of realNumber is set on real in the database.
is it possible to use real or integer variables without converting to string?
Thanks

Answer 1

Depending on the version of Python, sample code below don't require a type conversion: (Note: to avoid sql injection option 4 is best.)
def func1(ag):
return f" variable {ag}"
def func2(ag):
return "SELECT numColumn from numTable WHERE realNumber=?", ( ag )
def func3(ag):
return f"SELECT numColumn from numTable WHERE realNumber={ag}"
def func4(ag):
sql = "SELECT numColumn from numTable WHERE realNumber={}"
return sql.format(ag)
ag = 40.5
print(func1(ag))
print(func2(ag))
print(func3(ag))
print(func4(ag))
Output:
variable 40.5
('SELECT numColumn from numTable WHERE realNumber=?', 40.5)
SELECT numColumn from numTable WHERE realNumber=40.5
SELECT numColumn from numTable WHERE realNumber=40.5
#---------------Original code in question-----------------
from tkinter import*
import tkinter as tk
from tkinter import ttk
import sqlite3
realNumber = 2.0
database = sqlite3.connect('NumDB.db')
cursor = database.cursor()
cursor.execute("SELECT numColumn from numTable WHERE realNumber={}".format(realNumber) )
results = cursor.fetchall()
print(results)
cursor.close()
database.close()