我有一个问题，如何显示父母和孩子： 这是我的例子： T1是T2的父母。
ID create datetime(mm/dd/yyyy hh:mm:ss)
1 17-Apr-2016
2 18-Apr-2016
3 13-Apr-2016
4 15-Apr-2016
5 20-Apr-2016
6 19-Apr-2016
ID(FK) seq create datetime(mm/dd/yyyy hh:mm:ss)
1 6546 20-Apr-2016
1 5457 19-Apr-2016
1 4245 18-Apr-2016
1 0
2 5567 19-Apr-2016
2 0
3 2034 15-Apr-2016
3 1987 14-Apr-2016
3 1902 14-Apr-2016
3 1249 13-Apr-2016
3 0
4 2209 15-Apr-2016
4 2456 16-Apr-2016
4 3578 17-Apr-2016
4 3467 17-Apr-2016
4 4645 18-Apr-2016
4 5357 19-Apr-2016
4 0
5 0
6 0
T2是T1的子节点，A和B是我想根据我的条件显示的文本值，这不是来自db。我的条件是：
理想情况下，我的输出是：
Id createtime Type
1 17-Apr-2016 A
1 20-Apr-2016 B
2 18-Apr-2016 A
2 19-Apr-2016 B
3 13-Apr-2016 A
3 15-Apr-2016 B
4 15-Apr-2016 A
4 15-Apr-2016 B
5 20-Apr-2016 A
6 19-Apr-2016 A
编辑：我还必须添加日期/时间过滤器 T1.createatetime在to_date（2016年4月1日）和to_date（2016年4月30日）之间 要么 在to_date（2016年4月1日至2016年）和to_date（2016年4月30日）之间的T2.createdate时间
答案 0 :(得分：0)
我认为工会应该这样做：
WITH T1 as(
select 1 ID, '17-Apr-2016' as crte from dual union all
select 2 ID, '18-Apr-2016' as crte from dual union all
select 3 ID, '13-Apr-2016' as crte from dual union all
select 4 ID, '15-Apr-2016' as crte from dual union all
select 5 ID, '20-Apr-2016' as crte from dual union all
select 6 ID, '19-Apr-2016' as crte from dual
)
,
T2 as(
select 1 ID, 6546 SEQ, '20-Apr-2016' as crte from dual union all
select 1 ID, 5457 SEQ, '19-Apr-2016' as crte from dual union all
select 1 ID, 4245 SEQ, '18-Apr-2016' as crte from dual union all
select 1 ID, 0 SEQ, NULL as crte from dual union all
select 2 ID, 5567 SEQ, '19-Apr-2016' as crte from dual union all
select 2 ID, 0 SEQ, NULL as crte from dual union all
select 3 ID, 2034 SEQ, '15-Apr-2016' as crte from dual union all
select 3 ID, 1987 SEQ, '14-Apr-2016' as crte from dual union all
select 3 ID, 1902 SEQ, '14-Apr-2016' as crte from dual union all
select 3 ID, 1249 SEQ, '13-Apr-2016' as crte from dual union all
select 3 ID, 0 SEQ, NULL as crte from dual union all
select 4 ID, 2209 SEQ, '15-Apr-2016' as crte from dual union all
select 4 ID, 2456 SEQ, '16-Apr-2016' as crte from dual union all
select 4 ID, 3578 SEQ, '17-Apr-2016' as crte from dual union all
select 4 ID, 3467 SEQ, '17-Apr-2016' as crte from dual union all
select 4 ID, 4645 SEQ, '18-Apr-2016' as crte from dual union all
select 4 ID, 5357 SEQ, '19-Apr-2016' as crte from dual union all
select 4 ID, 0 SEQ, NULL as crte from dual union all
select 5 ID, 0 SEQ, NULL as crte from dual union all
select 6 ID, 0 SEQ, NULL as crte from dual
)
select ID, crte, 'A' Type from T1 where crte between to_date('01-Apr-2016') and to_date('30-Apr-2016')
union
select ID, max(crte), 'B' Type from T2 where seq <> 0 and crte between to_date('01-Apr-2016') and to_date('30-Apr-2016') group by ID;
输出：
ID CRTE TYPE
---------- ----------- ----
1 17-Apr-2016 A
1 20-Apr-2016 B
2 18-Apr-2016 A
2 19-Apr-2016 B
3 13-Apr-2016 A
3 15-Apr-2016 B
4 15-Apr-2016 A
4 19-Apr-2016 B
5 20-Apr-2016 A
6 19-Apr-2016 A
答案 1 :(得分：0)
这样的事情......请注意，我更改了输入数据，以便涵盖所有可能的组合（我认为）。
with t1 (id, create_datetime) as
( select 1, date '2016-04-17' from dual union all
select 2, date '2016-04-18' from dual union all
select 3, date '2016-04-10' from dual
),
t2 (id, seq, create_datetime) as
(
select 1, 6546, date '2016-04-20' from dual union all
select 1, 5457, date '2016-04-19' from dual union all
select 1, 4245, date '2016-04-18' from dual union all
select 1, 0 , null from dual union all
select 2, 5567, date '2016-04-19' from dual union all
select 2, 4003, date '2016-04-21' from dual union all
select 3, 0 , null from dual
)
select t1.id, t1.create_datetime, 'A' as type
from t1 join t2 on t1.id = t2.id
where t2.seq = 0
and t1.create_datetime >= date '2016-04-01'
and t1.create_datetime < date '2016-05-01'
union all
select id, max(create_datetime), 'B'
from t2
where create_datetime >= date '2016-04-01'
and create_datetime < date '2016-05-01'
group by id
order by id, type;
输出（使用WITH子句中定义的t1和t2中的数据）：
ID CREATE_DATE TYPE
---------- ----------- ----
1 17-Apr-2016 A
1 20-Apr-2016 B
2 21-Apr-2016 B
3 10-Apr-2016 A
答案 2 :(得分：0)
您可以在没有联合的情况下执行此操作，并且在每个表上仅使用一次表扫描：
Oracle安装程序：
CREATE TABLE T1 ( ID, CRTE ) AS
select 1, DATE '2016-04-17' FROM DUAL UNION ALL
select 2, DATE '2016-04-18' FROM DUAL UNION ALL
select 3, DATE '2016-04-13' FROM DUAL UNION ALL
select 4, DATE '2016-04-15' FROM DUAL UNION ALL
select 5, DATE '2016-04-20' FROM DUAL UNION ALL
select 6, DATE '2016-04-19' FROM DUAL;
CREATE TABLE T2 ( ID, SEQ, CRTE ) AS
select 1, 6546, DATE '2016-04-20' FROM DUAL UNION ALL
select 1, 5457, DATE '2016-04-19' FROM DUAL UNION ALL
select 1, 4245, DATE '2016-04-18' FROM DUAL UNION ALL
select 1, 0, NULL FROM DUAL UNION ALL
select 2, 5567, DATE '2016-04-19' FROM DUAL UNION ALL
select 2, 0, NULL FROM DUAL UNION ALL
select 3, 2034, DATE '2016-04-15' FROM DUAL UNION ALL
select 3, 1987, DATE '2016-04-14' FROM DUAL UNION ALL
select 3, 1902, DATE '2016-04-14' FROM DUAL UNION ALL
select 3, 1249, DATE '2016-04-13' FROM DUAL UNION ALL
select 3, 0, NULL FROM DUAL UNION ALL
select 4, 2209, DATE '2016-04-15' FROM DUAL UNION ALL
select 4, 2456, DATE '2016-04-16' FROM DUAL UNION ALL
select 4, 3578, DATE '2016-04-17' FROM DUAL UNION ALL
select 4, 3467, DATE '2016-04-17' FROM DUAL UNION ALL
select 4, 4645, DATE '2016-04-18' FROM DUAL UNION ALL
select 4, 5357, DATE '2016-04-19' FROM DUAL UNION ALL
select 4, 0, NULL FROM DUAL UNION ALL
select 5, 0, NULL FROM DUAL UNION ALL
select 6, 0, NULL FROM DUAL;
<强>查询：
SELECT T1.id,
COALESCE( T2.CRTE, T1.CRTE ) AS CRTE,
CASE SEQ WHEN 0 THEN 'A' ELSE 'B' END AS Type
FROM T1
INNER JOIN
( SELECT t.*,
CASE SEQ WHEN 0 THEN 1
ELSE ROW_NUMBER() OVER ( PARTITION BY ID
ORDER BY CRTE DESC
NULLS LAST )
END AS RN
FROM T2 t ) T2
ON ( t1.ID = t2.ID AND t2.RN = 1 )
ORDER BY id, type;
<强>输出：
ID CRTE TYPE
---------- ------------------- ----
1 2016-04-17 00:00:00 A
1 2016-04-20 00:00:00 B
2 2016-04-18 00:00:00 A
2 2016-04-19 00:00:00 B
3 2016-04-13 00:00:00 A
3 2016-04-15 00:00:00 B
4 2016-04-15 00:00:00 A
4 2016-04-19 00:00:00 B
5 2016-04-20 00:00:00 A
6 2016-04-19 00:00:00 A
查询2 - 使用过滤器：
SELECT T1.id,
COALESCE( T2.create_datetime, T1.create_datetime ) AS create_datetime,
CASE SEQ WHEN 0 THEN 'A' ELSE 'B' END AS Type
FROM T1
INNER JOIN
( SELECT T2.*,
CASE SEQ WHEN 0 THEN 1
ELSE ROW_NUMBER() OVER ( PARTITION BY ID
ORDER BY create_datetime DESC
NULLS LAST )
END AS RN
FROM T2
WHERE create_datetime IS NULL
OR create_datetime BETWEEN DATE '2016-04-01'AND DATE '2016-04-30'
) T2
ON ( t1.ID = t2.ID AND t2.RN = 1 )
WHERE T1.create_datetime BETWEEN DATE '2016-04-01'AND DATE '2016-04-30'
ORDER BY id, type;
<强>输出：
ID CREATE_DATETIME TYPE
---------- ------------------- ----
1 2016-04-17 00:00:00 A
1 2016-04-20 00:00:00 B
2 2016-04-18 00:00:00 A
2 2016-04-19 00:00:00 B
3 2016-04-13 00:00:00 A
3 2016-04-15 00:00:00 B
4 2016-04-15 00:00:00 A
4 2016-04-19 00:00:00 B
5 2016-04-20 00:00:00 A
6 2016-04-19 00:00:00 A