what is the use of preselect?
how to fetch a record using preselect?
what is the main difference between preselect and for each?
There are several pages that discuss this topic under the heading "PRESELECT phrase" in the 4GL Reference manual.
Have you tried looking for an answer? Where have you looked? What have you found? What are you trying to achieve? Are you trying to pass an exam? If so, then learning to find the answers by looking at the documentation and Google searches will stand you in far better stead in the long run than asking on here. There should be plenty of information on what you want on the web.
Which Part of the documentation is unclear about that? Do you have a more precise question?
I would also recommend to use a more meaningful subject for your threads.=
There are several pages that discuss this topic under the heading "PRESELECT phrase" in the 4GL Reference manual.