In the following pl sql program what is the error ? Is it a compilation error?
<pre><code>Declare
 a VARCHAR2(10);
 b NUMBER;
BEGIN 
 a:=&amp;empname;
 b:=&amp;empno;
 DBMS_OUTPUT.PUT_LINE('WELCOME'a||','||b||);
END;
</code></pre>

<p>When I am running it on oracle sql developer,  it is showing some some which I can not able to figure out.</p>