title: Using a variable in an SQL query (Oracle DBMS)?
body: <p>I am typing SQL queries to get some data from a software tool which is based on an Oracle database. I am using the typical <code>SELECT</code>-statement.</p>
  
  <p>Now, in my SQL-query I am using at different places the date "02.05.2012". Is there a way to define a variable <code>date_string</code> at the beginning and then use at all relevant places this variable?</p>
  
  <p>This would simplify things a lot. Thanks for all hints and tips!</p>