Retrieve data from sql server database using Python

Question

I am trying to execute the following script. but I don’t get neither the desired results nor a error message ,and I can’t figure out where I’m doing wrong.

import pyodbc 
cnxn = pyodbc.connect("Driver={SQL Server Native Client 11.0};"
                        "Server=mySRVERNAME;"
                        "Database=MYDB;"
                        "uid=sa;pwd=MYPWD;"
                        "Trusted_Connection=yes;")


cursor = cnxn.cursor()
cursor.execute('select DISTINCT firstname,lastname,coalesce(middlename,' ') as middlename from Person.Person')

for row in cursor:
    print('row = %r' % (row,))

any ideas ? any help is appreciated 🙂

Asked By: Mohamed Azizi

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Source

Answer 1

You have to use a fetch method along with cursor. For Example

for row in cursor.fetchall():
    print('row = %r' % (row,))

EDIT :

The fetchall function returns all remaining rows in a list.

    If there are no rows, an empty list is returned. 
    If there are a lot of rows, *this will use a lot of memory.*

Unread rows are stored by the database driver in a compact format and are often sent in batches from the database server.

Reading in only the rows you need at one time will save a lot of memory.

If we are going to process the rows one at a time, we can use the cursor itself as an interator
Moreover we can simplify it since cursor.execute() always returns a cursor :

for row in cursor.execute("select bla, anotherbla from blabla"): 
    print row.bla, row.anotherbla

Documentation

Answered By: Hari Krishnan

Answer 2

I found this information useful to retrieve data from SQL database to python as a data frame.

import pandas as pd
import pymssql

con = pymssql.connect(server='use-et-aiml-cloudforte-aiops- db.database.windows.net',user='login_username',password='login_password',database='database_name')
cursor = con.cursor()

query = "SELECT * FROM <TABLE_NAME>"
cursor.execute(query)
df = pd.read_sql(query, con)
con.close()

df

Answered By: Palash Mondal

Answer 3

import mysql.connector as mc

connection creation

conn = mc.connect(host=’localhost’, user=’root’, passwd=’password’)
print(conn)

#create cursor object

cur = conn.cursor()
print(cur)

cur.execute(‘show databases’)

for i in cur:
print(i)

query = "Select * from employee_performance.employ_mod_recent"
emp_data = pd.read_sql(query, conn)
emp_data

Answered By: raju botta

Answer 4

How do I view them as a table? it is displaying like tuples.

I have multiples tables in DW , how do I load them all as table in Jupyter notebook?

Answered By: Sriram Varma

Retrieve data from sql server database using Python

Question:

Answers:

connection creation