title: What does "variable = ." (variable = dot) mean in Oracle SQL/SAS?
body: <p>I am converting a SAS script to Python, where the SAS script was interfacing with an Oracle database, and the Python will be interfacing with a PostgreSQL database. In the SAS code, I found this statement:</p>
  
  <pre><code>proc sql noprint;
  create table table_name as
    select distinct wtn
      from another_table
     where account = .
  ;
  </code></pre>
  
  <p>What does "where account = ." mean in Oracle? Or is it not an Oracle SQL thing, and instead is a SAS thing? Or is it available in all forms of SQL?</p>
  
  <p>Further, if it is SAS and/or Oracle specific, what would I use in PostgreSQL in its place?</p>