Sorting query results - sql

Question

How can I properly sort the results to show the results in the following order
1st - Parent Name
2nd - Child Name
3rd - Teacher Name
4th - Other Name
Where the parent name and child name is on the same table Family
id | parent name | child name
-----------------------------
1 Denz Hanz
2 Denz Pog
3 Joann Mac
while the other names are on different tables teacher table
id | teacher name
-----------------
1 Miguel
2 Sean
and Other_guest table
id | guest name
-----------------
1 Mike
2 Mal
where in cases that the parent did not arrive, the child name will be showed. Result of the query should show something like this
Participant Name
----------------
1. Denz
2. Denz
3. Mac
4. Miguel
5. Sean
6. Mal
7. Mike
I tried using order by field(),order by field asc, field2 dec ... etc but it seems not the result we wanted.

Answer 1

Below query works in most of the databases, this query will first sort by type and then name:
select * from (
select parent_name, 0 sort_by from table1
union all
select chile_name, 1 from table1
union all
select teacher_name, 2 from table2
union all
select guest_name, 3 from table3) t
order by sort_by, parent_name;

Answer 2

Here is my solution for Oracle DB:
Note that the UNION does not allow ORDER BY clause in subsequent select statements, therefore a procedure is necessary that generates the list of guests in the GUESTS table.
The table ARRIVED contains the IDs of the arrived parents, all other tables are self explanatory.
create table Family (id number, parentname varchar2(100), childname varchar2(100));
create table Teacher (id number, teachername varchar2(100));
create table Other_guest (id number, guestname varchar2(100));
create table Arrived (id number);
create table Guests (guestname varchar2(100));
create sequence Family_seq start with 1 order;
create sequence Teacher_seq start with 1 order;
create sequence Other_seq start with 1 order;
create or replace trigger Family_id before insert on Family for each row
begin
select Family_seq.nextval into :new.id from dual;
end;
create or replace trigger Teacher_id before insert on Teacher for each row
begin
select Teacher_seq.nextval into :new.id from dual;
end;
create or replace trigger Other_id before insert on Other_guest for each row
begin
select Other_seq.nextval into :new.id from dual;
end;
insert into Family (parentname, childname) values ('Denz', 'Hanz');
insert into Family (parentname, childname) values ('Denz', 'Pog');
insert into Family (parentname, childname) values ('Joann', 'Mac');
insert into Teacher (teachername) values ('Miguel');
insert into Teacher (teachername) values ('Sean');
insert into Other_guest (guestname) values ('Mike');
insert into Other_guest (guestname) values ('Mal');
insert into Arrived (id) values (1);
insert into Arrived (id) values (2);
create or replace procedure update_guest_list as
pragma autonomous_transaction;
cursor c_parents is select parentname from family where id in (select id from arrived) order by family.parentname;
cursor c_children is select childname from family where id not in (select id from arrived) order by family.childname;
cursor c_teachers is select teachername from teacher order by teacher.teachername asc;
cursor c_others is select guestname from other_guest order by other_guest.guestname asc;
begin
delete from guests;
for parents_rec in c_parents
loop
insert into guests (guestname) values (parents_rec.parentname);
end loop;
for children_rec in c_children
loop
insert into guests (guestname) values (children_rec.childname);
end loop;
for teachers_rec in c_teachers
loop
insert into guests (guestname) values (teachers_rec.teachername);
end loop;
for others_rec in c_others
loop
insert into guests (guestname) values (others_rec.guestname);
end loop;
commit;
end;
/
execute update_guest_list;