TblName1 = Your1stTabel
TblName2 = Your2ndTabel

sele (TblName1)
for i=1 to fcount()
   FldName = fields(i)
   FldName1 = TblName1 +"."+ FldName
   FldName2 = TblName2 +"."+ FldName
   if &FldName1 <> &FldName2
      * *** difference
      exit
   endif
endfor