You have to be more specific. From what you have provided one can only guess. My guess is that you want to export your data to a text file. If that is correct, you can either use proc export or, if you need more control, take a look at:
You ask this question in your post:
Basically, T_LST table is a work table that is created, So I do not know how to access it ?
You would access T_LST by either a ONE-level or TWO-level name in a DATA step program. Either WORK.T_LST or just T_LST. If you mean that your SAS session ends and you need to get to T_LST in a new session, then you would either have to run your SQL step again or create T_LST in a permanent library. Something like:
libname KEEPABIT 'c:\temp\mydata';
create table KEEPABIT.T_LST as select
a.Cust_ID, a.S_ID, a.fld_txt
group by 1, 2;
proc sort data=work.t_lst out=keepabit.t_lst;
About your code:
If first.s_id then lngname = ' ';
Some kind of loop - Trim(fld_txt) ||
If last.s_id then Output;
I believe that "Some kind of loop - Trim(fld_txt) || " has been explained or discussed in some of the answers to your previous posts.