title: Match number and list column headings in one cell
body: <p>I have a worksheet that has a summary sheet which keeps all the data and several other data sheets that are used to confirmed the information. I like to match the identifying number on the summary sheet with the number on the data sheet and list the column letters, in one cell, where the condition is not met. </p>
  
  <p>Also the data sheet will be updated which will affect the result of the conditional statement but I want to be able to preserve the historical result of the first results. </p>
  
  <p>*The identifying numbers are not unique but there should never be a situation this would cause different data to be returned. </p>
  
  <p>Is this possible?</p>