title: Update only month and date of string in MySQL/PHP
body: <p>I am trying to update only the month and the day of a string. So example given: In my database i have a <code>DATETIME</code> column. Let's say that has the value <code>2018-01-08 00:00:00</code>. The user gives in another date which he would like to update. E.g. <code>2017-11-07 00:00:00</code>. I have a check on the code which descides if the date is different. So we'll skip that. I only want to update the month and the day of that string. So i don't want to update the time and year. The name of my <code>DATETIME</code> column is <code>upDatum</code> I've searched everywhere for this but there is no concrete answer. Here is what i have:</p>
  
  <pre><code>$query = "UPDATE twh_uren_prognose SET upUren = 
  ".$key['inputupuren'].", MONTH(upDatum) = ".$month.", DAY(upDatum) = 
  ".$day." WHERE upID = ".$key['inputupid'];
  </code></pre>
  
  <p>My question is: How can i only <code>UPDATE</code> the month and the day of a <code>DATETIME</code> MySQL column. I'm a little stuck. The Query which i'm talking about goes like this:</p>
  
  <p>I hope this is kinda clear! Thanks! </p>