title: Oracle - Handle empty resultset on IF THEN ELSE statement
body: <p>which should be the IF condition when the variable assignation results from an empty resultset?</p>
  
  <p>Example:</p>
  
  <pre><code>CREATE OR REPLACE Function get_values
       ( chv_input IN varchar2 )
       RETURN varchar2
  IS
       chv_output varchar2(100);
  
    BEGIN
  
  select 'value'
      into chv_output
  from dual where 1=2; 
  
  IF chv_output is null THEN --this condition is not working
  
      chv_output := 'null';
  
  ELSE
       chv_output := 'not null';
  
  END IF;
  
    RETURN chv_output;
  
  END;
  
  --select 1, get_values('112') from dual
  </code></pre>