title: Generate Unique Number
body: <p>I have an SQL Query </p>
  
  <pre><code>select substring(
              replace(
                  replace(
                      replace(
                          replace(
                              convert(varchar,sysdatetime(),121),
                          '-',''),
                      ' ',''),
                  ':',''),
              '.','')
          ,1,18) as DATETIME
  </code></pre>
  
  <p>It is generating 18 digits Current Number like <code>201605011221374719</code></p>
  
  <p>How can I change this query to generate 11 digits Unique Numbers ?</p>