title: increase column value manual
body: <p>I have id column in postgres which is not serial that is integer. It have 1 to 3 values while rows of this column more than 100. I want to assign values to empty rows as 4,5,6 continuously through query. This is example, while I have a lot of records in a table. So help me how to update an id column with a query</p>
  
  <pre><code>select id, name from xyz order by id;  
  
              id | name
              1  | a
              2  | b
              3  | c
                 | d
                 | e
                 | f
  </code></pre>
  
  <p>wanted result</p>
  
  <pre><code>select id, name from xyz order by id;
  
      id | name
      1  | a
      2  | b
      3  | c
      4  | d
      5  | e
      6  | f
  </code></pre>
  
  <p>Below lines only for submit question please don't consider it:</p>
  
  <pre><code>select id ,name,date_time,(select 'wasa'::text) as link from abc 
  union
  select x.id+max(a.id),x.name,x.date_time,(select 'uu'::text) as link from xyz x ,abc a
  group by x.id
  order by id
  </code></pre>