title: Update MSSQL table through SQLAlchemy using dataframes
body: <p>I'm trying to replace some old MSSQL stored procedures with python, in an attempt to take some of the heavy calculations off of the sql server. The part of the procedure I'm having issues replacing is as follows</p>
  
  <pre><code>UPDATE mytable
  SET calc_value = tmp.calc_value
    FROM dbo.mytable mytable INNER JOIN 
         @my_temp_table tmp ON mytable.a = tmp.a AND mytable.b = tmp.b AND mytable.c = tmp.c
    WHERE (mytable.a = some_value)
      and (mytable.x = tmp.x)
      and (mytable.b = some_other_value)
  </code></pre>
  
  <p>Up to this point, I've made some queries with SQLAlchemy, stored those data in Dataframes, and done the requisite calculations on them. I don't know now how to put the data back into the server using SQLAlchemy, either with raw SQL or function calls. The dataframe I have on my end would essentially have to work in the place of the temporary table created in MSSQL Server, but I'm not sure how I can do that.</p>
  
  <p>The difficulty is of course that I don't know of a way to join between a dataframe and a mssql table, and I'm guessing this wouldn't work so I'm looking for a workaround</p>