I have a list of part numbers, all of them have 7 digit. Some only have 7 digits only, some have 7 digits followed by a dash and 1 letter, some have 7 digits followed by a dash and 2 letters, and some have 7 digits followed by a dash and 3 letters.

Example:
1234567
1234569
1234561-S
1234747-DAL
1234568-LP

How do I get them to sort to where the 7 digits are in numeric order? Right now, all the parts with just 7 digits are at the top, followed by the parts that have the letters at the bottom.

Thank for your help.