title: How to delete from table if count is greater than 20
body: <p>I have a mysql table that I need to only contain 20 newest records before adding additional records.
  New rows are added daily so I would like it first delete any records that are greater than the 20 allowed starting with the earliest.</p>
  
  <p>The table contains an auto increment "id" column so I can easily determine which is the earliest records.</p>
  
  <p>Thanks for any help.</p>