title: How to make an INSERT with substitution variable and use that variable value on a SUBSTR?
body: <p>I have this query. What it does is ask me for a value for <strong>&amp;last_name</strong> and <strong>&amp;first_name</strong> and use those values for the SUBSTRs, but it stores the value unless I use the <strong>UNDEFINE <em>variable</em></strong> afterwards.</p>
  
  <pre><code>INSERT INTO my_employee (id, last_name, first_name, userid, salary)
  VALUES(3, '&amp;&amp;last_name', '&amp;&amp;first_name', 
  LOWER(SUBSTR('&amp;first_name', 1, 1)||SUBSTR('&amp;last_name', 1, 7)), 1100);
  
  UNDEFINE last_name
  UNDEFINE first_name;
  </code></pre>
  
  <p>What I want is to make it so it asks me for a value for <strong>last_name</strong> and <strong>first_name</strong> each time I run the query, and to use that value for the SUBSTR concatenation, so I dont have to use the UNDEFINE and can freely reuse the query over and over if I want.</p>
  
  <p>Thank you for your help. :)</p>