title: Why NAN values while fetching data?
body: <pre><code>from sqlalchemy import create_engine
  import pymysql
  import pandas as pd
  
  db_connection_str='mysql+pymysql://username:pwd@Host/DB'
  db_connection = create_engine(db_connection_str)
  
  df = pd.read_sql('select * from tbl_store_inventory', con=db_connection)
  print(df)
  </code></pre>
  
  <p>After executing this code, I'm getting NAN value for all the columns. Why?</p>