title: Merge dataframes by left join SQL & Pandas
body: <p>I made two tables into a MySQL database using Python. The following SQL code is to perform join on two tables in the database. How can I do the same by writing equivalent python code?</p>
  
  <p>MySQL code:</p>
  
  <pre><code>SELECT A.num, B.co_name, A.rep_name
  FROM A 
  JOIN B 
  ON A.num=B.no
  </code></pre>
  
  <p>Desired Python codes:</p>
  
  <pre><code>sql = "XXX"    
  df_merged = pd.read_sql(sql, con=cnx)
  </code></pre>