from sqlalchemy import create_engine

cnx = create_engine('mysql+pymysql://username:password@server:3306/database').connect()
sql = 'select * from mytable'
df = pd.read_sql(sql, cnx)

To fetch large data we can use generators in pandas and load data in chunks.

import pandas as pd
from sqlalchemy import create_engine
from sqlalchemy.engine.url import URL


# sqlalchemy engine
engine = create_engine(URL(
    drivername="mysql"
    username="user",
    password="password"
    host="host"
    database="database"
))

conn = engine.connect()

generator_df = pd.read_sql(sql=query,  # mysql query
                           con=conn,
                           chunksize=chunksize)  # size you want to fetch each time

for dataframe in generator_df:
    for row in dataframe:
        pass  # whatever you want to do