PHV,
Here is the SQL code for 2 calculated fields, the second one (col) giving the sorting problems.
IIf([pos_sur_plaque]<>"",Left([pos_sur_plaque],1),"") AS row
IIf([row]<>"",Val(Replace([pos_sur_plaque],[row],"")),"") AS col
where:
[pos_sur_plaque] is an alphanumeric chain in the style of...