title: Add a row at the end of SQL Select using UNION
body: <p>I created a view in a record using some filters and i have to add lines that contains just ids from another table and a specific row at the end of the sql result.</p>
  
  <p>So the expected result is something like that:</p>
  
  <pre><code>    Column 1 | Column 2 | Column 3 | Column4
  1   0001     | 565      | AM1      | DR01
  .
  .
  59  TEST1    |          |          |
  60  NON_IMMO |          |          |
  </code></pre>
  
  <p>Line 59 is the id from the second table and line 60 is the specifix row.
  My query is like that :</p>
  
  <pre><code>SELECT DISTINCT a.asset_id 
   , a.serial_id 
   , a.VIN 
   , b.project_id 
    FROM ps_asset a 
   WHERE --Some conditions  
    UNION 
   SELECT PO_GROUP_ID 
   ,' ' 
   , ' ' 
   , ' ' 
    FROM PS_PO_GROUP_TBL 
    UNION 
   SELECT 'NON_IMMO' 
   ,' ' 
   ,' ' 
   ,' ' 
    FROM dual
  </code></pre>
  
  <p>But the problem is using this I don't get the specific row at the end.</p>
  
  <p>I feel like the SGBD show the 2 UNIONS ordered by alphabet.</p>
  
  <pre><code>    Column 1 | Column 2 | Column 3 | Column4
  1   0001     | 565      | AM1      | DR01
  .
  .
  59  NON_IMMO |          |          |
  60  TEST1    |          |          |
  </code></pre>
  
  <p>Thanks for help.</p>