String as date (conversion)

Hi,

Can someone help me out please with a UDF that gets an input string, but it needs to look at that string as if it is a date, and then transform that string to another format.

The input string can be empty or contain 8 zeroes ("" or "00000000") and if that happens the UDF must return "", and of course no transformation can be done then.

If the string is not empty or zeroes, the transformation will be yyyymmdd to dd-mm-yyyy.

Kind regards

Robert