Question

如何正确排序结果以按以下顺序显示结果

1st - Parent Name   
2nd - Child Name  
3rd - Teacher Name  
4th - Other Name

父名称和子名称在同一个表Family

上

id | parent name | child name
-----------------------------  
1    Denz          Hanz  
2    Denz          Pog  
3    Joann         Mac

而其他名称在不同的教师表上

id | teacher name  
-----------------  
1     Miguel  
2     Sean

和Other_guest表

id | guest name
-----------------
1   Mike  
2   Mal

如果父母没有到达，则会显示子名称。查询结果应该显示类似这样的内容

Participant Name
----------------
1. Denz 
2. Denz  
3. Mac 
4. Miguel 
5. Sean  
6. Mal 
7. Mike

我尝试使用order by field（），按字段asc，field2 dec ...等排序，但似乎不是我们想要的结果。

Answer 1

以下查询适用于大多数数据库，此查询将首先按类型排序，然后命名：

SELECT CustomerID,CustomerName,OrderValue
FROM Customers 
WHERE CustomerID IN (SELECT CustomerID
                     FROM Orders
                     WHERE OrderValue > 10000
                    )

Answer 2

以下是我对Oracle DB的解决方案：

请注意，UNION在后续select语句中不允许使用ORDER BY子句，因此需要一个过程来生成GUESTS表中的guest虚拟机列表。

表ARRIVED包含到达父项的ID，所有其他表都是自解释的。

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;

对查询结果进行排序

2 个答案: