How to make a query for two tables in two different servers (python)?

Question

I'm stuck a bit with a following problem:

I have two different servers within separated tables: Oracle with table "A" and PostgreSQL with table "B".

I`m trying to make a program via python, which joins these two tables and writes the result into csv file.

What is the best way to do it? (Importing a table from one db to another? Making a JOIN outside the db?)

Would be happy for your help!

Answer 1

import cx_Oracle
from sqlalchemy import create_engine
import pandas as pd

engineORACLE = create_engine('oracle://user:password@ip:1521/ORACLE_SERVIVE_NAME')
enginePOSTGRE = create_engine('postgresql://user@lip:5432/mydb')

df1 = pd.read_sql_query('select * from tableA', con=engineORACLE)    
df2 = pd.read_sql_query('select * from TableB',con=enginePOSTGRE)

dfcombined = df1.merge(df2, on='blabla', how='left') # for left outer join, you can also do, 'right', 'outer' or 'inner' (change 'blabla' with the key!)

Something like this?