title: MSSQL Check if column is all digits or empty
body: <p>I have a varchar field in a table. I have to check which rows contain anything but digits (0-9). Any other character (. , etc) are not allowed.</p>
  
  <p>ISNUMERIC isn't helpful because the string can get longer than anything which would be convertible to a numeric datatype in SQL-Server.</p>
  
  <p>Any ideas on how to do this?</p>
  
  <p>Thanks a lot!</p>