Join in dynamic way

Question

Hi,
I want to do dynamic join from 3 tables and give the i.e. i have method with import fields
and i want to do the select accordingly to the fields that i have
if user enter 5 fields do the select just from table one
if user enter 10 fields to the select from 2 tables (because the additional 5 fields
are form table number 2
and if user enter 15 fields do the same for the third table.
There is option to do it in one dynamic join ?
Regards
Joy
Edited by: Joy Stpr on Aug 4, 2009 6:39 AM
Moderator comments: I have deleted the other two threads as
you can continue and build on the suggestions given against this
thread. PL don't create multiple threads on the same topic.
~Suresh
Edited by: Suresh Datti on Aug 9, 2009 10:33 PM

Answer 1

Hello Joy,
Try this way:
if all of your tables are transparent then it is easy to do:
1. define one single column internal table which will hold fields which you need to select. for e,g, <field>
2. Load required fields in to table <field>
3. Now describe table <field> and get the row count.
4. use case to switch between the select statement so if fields are five it is pretty simple to select data from
    single table and if it is 10 then you can use join from two table.
    Now before going to join you need to prepare a selected field string using respective alias which you can do
   by looping through <field> and then concatenating alias with fieldname use that string during seletion for e.g field_str
   Also you need table to hold data after select so you fieldcatalog_tab with <field> and pass it to below method
  call method cl_alv_table_create=>create_dynamic_table
exporting
  it_fieldcatalog = fieldcatalog_tab
  importing
      p_table = table.
This will give you dynamic internal table now depending on the case field catalog will have respective fields and out table
is create appropriately.
5. Repeat step 4 for case 3 that is join between 3 tables.
    Here again you need to create field_str which will hold selection fields with respective alias and
    dynamic internal table consist of all the 15 fields.
so your final select sudo code will be some thing like this:
DESCRIBE .... LINES.
case LINES
   when 5.
           select   (field_str)
             from   (table_name)
               into   <dyn_itab>
   when 10.
           select   (field_str)
             from   (table_name) --> here table_name consist of two table for e.g. ABCD AS A JOIN EFGH AS E ON A~XYZ EQ                                                                               
E~XYZ
               into   <dyn_itab>
when 15.
       Repeat same thing as case 10 only field_str and table_name and structure of <dyn_itab> will change.
endcase.
Hope this helps!,
Thanks,
Augustin.