Import CSV file into SQL Server using Python

Try d6tstack which has fast pandas to SQL functionality because it uses native DB import commands. It works for Postgres and MYSQL, MS SQL is experimental. Comment or raise an issue if it doesn't work.

import pandas as pd
df = pd.read_csv('cleanNVG.csv')
uri_mssql = 'mssql+pymssql://usr:pwd@localhost/db'
d6tstack.utils.pd_to_mssql(df, uri_mssql, 'table', 'schema') # experimental

It is also useful for importing multiple CSV with data schema changes and/or preprocess with pandas before writing to db, see further down in examples notebook

d6tstack.combine_csv.CombinerCSV(glob.glob('*.csv'), 
    apply_after_read=apply_fun).to_mssql_combine(uri_psql, 'table')

You are using csv.reader incorrectly. The first argument to .reader is not the path to the CSV file, it is

[an] object which supports the iterator protocol and returns a string each time its __next__() method is called — file objects and list objects are both suitable.

Hence, according to the example in the documentation, you should be doing something like this:

import csv
with open('cleanNVG.csv', newline='') as csvfile:
    customer_data = csv.reader(csvfile)
    for row in customer_data:
        cursor.execute(sql, tuple(row))

Check the data types on the table, and the sizes of each field as well. If it is varchar(10) and your data is 20 characters long, it will throw an error.

Also,

Consider building the query dynamically to ensure the number of placeholders matches your table and CSV file format. Then it's just a matter of ensuring your table and CSV file are correct, instead of checking that you typed enough ? placeholders in your code.

The following example assumes

CSV file contains column names in the first line
Connection is already built
File name is test.csv
Table name is MyTable
Python 3

...
with open ('test.csv', 'r') as f:
    reader = csv.reader(f)
    columns = next(reader) 
    query = 'insert into MyTable({0}) values ({1})'
    query = query.format(','.join(columns), ','.join('?' * len(columns)))
    cursor = connection.cursor()
    for data in reader:
        cursor.execute(query, data)
        cursor.commit()

If column names are not included in the file:

...
with open ('test.csv', 'r') as f:
    reader = csv.reader(f)
    data = next(reader) 
    query = 'insert into dbo.Test values ({0})'
    query = query.format(','.join('?' * len(data)))
    cursor = connection.cursor()
    cursor.execute(query, data)
    for data in reader:
        cursor.execute(query, data)
    cursor.commit()

Basically, though, your code looks fine. Here is a generic sample.

cur=cnxn.cursor() # Get the cursor
csv_data = csv.reader(file(Samplefile.csv')) # Read the csv
for rows in csv_data: # Iterate through csv
    cur.execute("INSERT INTO MyTable(Col1,Col2,Col3,Col4) VALUES (?,?,?,?)",rows)
cnxn.commit()