title: SUMIF with month criterion
body: <p>I have: </p>
  
  <pre><code>=SUMIF('Log'!A2:A139,MONTH('Log'!A2:A139)=1,'Log'!M2:M139)
  </code></pre>
  
  <p>Colums A in the 'Log' sheet contains dates. I want only to sum the values in the M column of the Log sheet IF the month is January.</p>
  
  <p>The current expression keeps on returning <code>0</code>, am I doing anything wrong?</p>