title: How to merge 2 tables with user and timestamp in python
body: <p>I need to merge 2 tables of millions of records. The common fields are user and timestamp. The problem is that the timestamp is different in both tables, so I need to create a new variable or establish a range of 5 seconds to find a perfect coincidence between tables 1 and 2.</p>
  
  <p>I am trying to use lookup or function y.  I am not an expert, so I really need your help.</p>
  
  <p>I know that it seems easy for an expert. Thank you very much!!!</p>