I am assuming you are asking about SQL/MP and SQLCI. If you are talking about SQL/MX and mxci, post again to say that is your environment.
There are a few things you can do.
1. If you don't need all of the columns to be displayed, you could list just the ones you need, which might make the line short enough to avoid the problem. Yes, it is both obvious and not applicable in many cases, but I did not want to overlook it.
2. I believe it is possible to use the command SET LAYOUT RIGHT_MARGIN 255; to make the logical line be 255 bytes long, then use the OUT_REPORT command to direct the output to an entry-sequenced file whose record length is defined as being at least 255. That would give you a bit longer line to work with, but still could be not enough for getting all of a table with many columns to display on one line. I can never be sure which NonStop programs allow output to entry-sequenced file and which do not. I am pretty sure that SQLCI does allow output to an entry-sequenced file, but if it does not accept entry-sequenced files in OUT_REPORT, then this won't work.
3. You could write a simple program that knows how many lines each row of the table takes up and have the program join the lines together. Suppose the rows take three lines to display. The program would read three lines, concatentate them, and write the combined line to an output file. If you are going to send that file to a PC to load into Excel, you might make the program write an unstructured file and have the program append carriage return and linefeed characters to the end of each combined line. Then you could transfer the file to the PC in binary mode and use it with no further changes.
4. You could explicitly list each column of the table in the SELECT list, and at the points where it would move to another line, insert some special literal in the SELECT list. Then after getting the data to the PC, use an editor that has a global search and replace that allows you to replace that literal followed by a carriage return and line feed with a blank. That would join all the lines for one row into a single line, then you could load the modified file into Excel.
There might be other ways to solve the problem, but these are the ones that occur to me immediately. If none of them are suitable for your case, post again and explain what it is about your problem that makes none of these ideas work, and we'll try to think of something that will work for you.