returning_list as an argument in prepare(), send_result_set_metadata() and
send_data(). It was returning all the fields from the insert table. Then I passed
returning_list as the argument and it is returning the listed fields but from the
select table. So now I am working on it by looking how select_insert class uses lex->field_list and do the same for returning_list.
Here is the link to code which returns the listed fields for select table:
https://github.com/rucha174/server/commit/6b18dd3cfc76d41871357c5b2006e04d1d508c1d