title: How to update only days of a date in SQL Server
body: <p>How to update all days in date column in table to special date?</p>
  
  <p>I want change only day, no month, no year </p>
  
  <p>My table:</p>
  
  <pre><code>id    RegisterDate
  ------------------
  1      2001-01-18
  2      2018-09-13
  3      1999-04-28
  4      2012-12-15
  </code></pre>
  
  <p>The result that I expect:</p>
  
  <pre><code>id    RegisterDate
  ------------------
  1      2001-01-02
  2      2018-09-02
  3      1999-04-02
  4      2012-12-02
  </code></pre>