As you can imagine from the name, NO_SUM does mostly opposite what DO_SUM, but in more secure way. If you don’t want that the field is allowed to be summarized, then set the value of this field to ‘X’. It will not only not show the sum, but also it will forbid to set it the GUI.
Figure 66 ZDEMO_AIN_CL28 DO_SUM for DISTANCE field
Once user will try to summarize the values of this column, he will get the message “Desired operation cannot be performed for column”.
Figure 67 ZDEMO_AIN_CL28 Message at try of making sum of DISTANCE field