Is there anyone know the steps on how to write a command to display value in a session without any duplicating values?

i get a 3 field value from a customize table for example tcxxx100 to display in a newly created session. but this 3 field is duplicated in table tcxxx100. So when i use it to display in the session it come out all duplicate value.

For example:
The results is:

A
A
A
B
B
C

The actual result that i want is:

A
B
C

Is there anyone have an idea to do this?

I don't know whether any command available or not in LN.

But in Baan IVc4 ; generally we use the skip.io function to skips the record in after.read subsection of main.table.io section.

main.table.io:
after.read:
if old.xxxx=tcxxx100.xxxx then
skip.io("")
else
old.xxxx=tcxxx100.xxxx
endif