Originally Posted by HuwGro
I need to sort on this field so that letters fall below numbers eg. 2, 1, 0, D, C, B, A and then the converted date. The first part is hard enough the second I think near impossible and I may have to resort to a second field in the table for the numerical date.
Your first sort isn't natively supported so you would be deriving another field just to sort it like that. Then the field for the modified date.
Your sort will be slow because every record will need to be read and processed. If it is a big table you may find it loads very slowly because all that processing has to complete before the first record loads.
If users are regularly subjected to this, it might be better to derive a value that can be sorted natively and save it when the records are inserted. An index on this field will allow the results to be sorted almost instantly giving your users a better experience.