title: how to solve this query using union
body: <p>Display id and name for salesmen along with id and category of products in a single table. Indicate the source of the row in result by adding an additional column TYPE with possible values as 'S' (Salesman) and 'P' (Product). Display all rows.</p>
  
  <p>I don't how to add column "type" without using alter</p>
  
  <pre><code>select sid AS ID,sname from salesman
  union
  select category as "DETAILS" from product
  </code></pre>
  
  <p>actual tables are</p>
  
  <p>Salesman Table</p>
  
  <pre><code>SID   SNAME    LOCATION
  1     Peter    London
  2     Michael  Paris
  3     John     Mumbai
  4     Harry    Chicago
  5     Kevin    London
  6     Alex     Chicago
  </code></pre>
  
  <p>Product Table</p>
  
  <pre><code>PRODID   PDESC           CATEGORY       DISCOUNT
  101      Basketball      Sports         5
  102      Shirt           Apparel        10
  103      NULL            Electronics    15
  104      CricketBat      Sports         20
  105      Trouser         Apparel        5
  106      Television      ELECTRONICS    20
  </code></pre>
  
  <p>expected output</p>
  
  <pre><code>TYPE  ID       DETAILS
  P     101      Sports
  P     102      Apparel
  P     103      Electronics
  P     104      Sports
  P     105      Apparel
  P     106      ELECTRONICS
  </code></pre>