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Fetch new data from SQL in python every few seconds-Exceptionshub

Posted by: admin February 24, 2020 Leave a comment

Questions:

I want to make a python script that consistently checks the Mysql database and prints out new updated records every few seconds.

import time
sql_conn = connectSQLServer('ODBC Driver 13 for SQL Server', 'D\SQLEXPRESS', 'display')

mycursor = sql_conn.cursor()

a = 0
while True:
    try:
        time.sleep(1)
        a=a+1
        print(a)
        sql = "SELECT id, val FROM dbo.LiveStatsFromSQLServer"    
        mycursor.execute(sql)

        myresult = mycursor.fetchall()

        for x in myresult:
            print(x)


    except Exception as error:
        print("Nothing in database\n")
        print(error)
sql_conn.commit()

Expected output:
The columns are (id, value)

1second
(1625, 3)
(1626, 0)
(1627, 10)
2second
(1625, 3)
(1626, 0)
(1627, 10)
3second
(1625, 3)
(1626, 0)
(1627, 10)
(1628,20)
How to&Answers:

Since your records appear to start with an auto-incrementing identifier, you could do:

sql = "SELECT id, val FROM dbo.LiveStatsFromSQLServer WHERE id > %s"
mycursor.execute(sql, prev_id)

And after the print(x) just add something like prev_id = x[0]:

    for x in myresult:
        print(x)
        prev_id = x[0]

Note: I don’t know what the actual first column of your result is called, just replace id with the actual column name in the script if you want to select * instead of naming the columns (and assuming there’s 2).