sql - sql 行值取决于其他行值

Question

我的表如下所示：

Name  | Text           |    GroupID
------------------------------------
A     | sometext       |    1
B     | x              |    2
C     | x              |    3
D     | sometext2      |    1
E     | x              |    2
F     | abc            |    
G     | sometext3      |    1
H     | x              |    2
I     | x              |    3

GroupID 1 -> 这是标题行，不应选择
GroupID 2-... -> IT 是上述标题的子行（ID = 1），应与标题行的文本一起选择！如果根本没有组 ID，则应选择不带文本的行

因此，当从上表中选择所有内容时，结果应该是：

 B    sometext    2
 C    sometext    3
 E    sometext2   2
 F             
 H    sometext3   2
 I    sometext3   3

有谁知道如何构建 select-stmt？

Answer 1

试试这个查询：

select 
 t1.name,
 case when t1.groupid is null then '' else 
 (select q.text from
   (select rownum as counter,name,text from TableName where groupid=1)q 
 where 
  q.counter = (select max(rownum) from TableName t2 where groupid=1 and
  t2.name<=t1.name))end as Text,
 t1.groupid 
from 
 TableName t1 
where 
 (t1.groupid<>1 or t1.groupid is null);

Answer 2

也试试这个（SQLFiddle 中的现场演示）：

-- here I return the headers without subheaders - GroupId NULL
select name, 
       case 
          when GroupID is null then null 
          else text 
       end header
from t
where groupid is null
union all
-- here I return the the others
select sub.name, 
       head.text
from t head
inner join (
              -- here I take for each sub the associated header
              select t.name, max(h.name) header
              from t
              inner join (select t.Name, t.Text from t where groupid = 1) h
                      on h.name < t.name
              where groupid > 1
              group by t.name
            ) sub on head.name = sub.header
order by 1