title: Update table in run time and the column not known in compile time
body: <p>I am trying to write the SQL to update multiple columns based on some code condition to the table in the code. </p>
  
  <p>For example, make it the easiest one in two columns  </p>
  
  <p><code>UPDATE table set A = valueA  where conditionA..</code></p>
  
  <p>OR  <code>UPDATE table set B=valueB where conditionA..</code></p>
  
  <p>OR <code>UPDATE table set A=valueA, B=valueB where conditionA..</code></p>
  
  <p>The condition is the same, but valueA/valueB may not exist depending on the code</p>
  
  <p>Is there any convenient way to combine them together in one SQL such as the select one <code>WHERE 1=1 and &lt;condition&gt;</code> so that I can add the conditions regardless one or more than one conditions? </p>
  
  <p>Hope it make sense.    </p>