title: DAX EARLIER() function in Power Query
body: <p>Is there an an equivalent to EARLIER in M/Power Query?</p>
  
  <p>Say, I have a table with lots of different dates in column DATE and a smaller number of letters in column LETTER. I now want the maximum date for each letter.</p>
  
  <p>In DAX, I would use something like CALCULATE(MAX([Date]),FILTER(ALL(Table),[Letter]=EARLIER([Letter])).</p>
  
  <p>How would I achieve the same in M?</p>
  
  <p>Thanks</p>