从循环输出Oracle SQL创建表

我需要从基于175个人口统计选项的约500万个观察数据表中随机抽取一个样本。人口统计表类似于以下表格：

1 40 4%
2 30 3%
3 30 3%
- -
174 2 .02%
175 1 .01%

基本上，我需要从500万行表格中随机抽取相同的人口统计数据。对于每个人口统计，我需要从较大的表中选择一个相同的样本，但观察次数为5倍。例如：对于人口统计1，我需要200个随机样本

SELECT  *
FROM    (
        SELECT  *
        FROM    my_table
        ORDER BY
                dbms_random.value
        )
WHERE rownum <= 100;

---

如果两个表中都存在1-175人口统计值，则可以联接表，或者有一个等效的列可以联接，例如：

select id
from (
  select d.demographic, d.percentage, t.id,
    row_number() over (partition by d.demographic order by dbms_random.value) as rn
  from demographics d
  join my_table t on t.demographic = d.demographic
)
where rn <= 5 * percentage

您只需要ID，但我包含上下文的其他列；或者更简洁地说：

with my_table (id, demographic) as (
  select level, mod(level, 175) + 1 from dual connect by level <= 175000
),
demographics (demographic, percentage, str) as (
            select 1, 40, '4%' from dual
  union all select 2, 30, '3%' from dual
  union all select 3, 30, '3%' from dual
  -- ...
  union all select 174, 2, '.02%' from dual
  union all select 175, 1, '.01%' from dual
)
select demographic, percentage, count(id) as ids, min(id) as min_id, max(id) as max_id
from (
  select d.demographic, d.percentage, t.id,
    row_number() over (partition by d.demographic order by dbms_random.value) as rn
  from demographics d
  join my_table t on t.demographic = d.demographic
)
where rn <= 5 * percentage
group by demographic, percentage
order by demographic;

DEMOGRAPHIC PERCENTAGE        IDS     MIN_ID     MAX_ID
----------- ---------- ---------- ---------- ----------
          1         40        200        175     174825
          2         30        150          1     174126
          3         30        150       2452     174477
        174          2         10      23448     146648
        175          1          5      19074     118649

---

你们有一张桌子还是两张桌子？我发现很难遵循数据结构。与这些百分比相关的数值是多少？@GordonLinoff我有两个。第一个表包含人口统计、百分比、观察次数数值。该表共有175行。第二张表是我想从中随机抽取的样本，约为500万rows@GordonLinoff我编辑了我的问题，试图使问题更清晰。你不必完全理解，主要的是我不知道从哪里开始循环不同表中的列并聚合结果。请回答你的问题，并为相关表添加CREATETABLE语句。您的示例数据只显示了两列，其中一列是PK？我仍然不清楚循环与通过列的需求循环有什么关系？。为什么要按dbms_random.value排序而不是使用normal子句？一些例子会很有帮助。第一段代码只需替换我的列名/表名就可以很好地工作，感谢您理解我的问题！

-- CTEs for sample data
with my_table (id, demographic) as (
  select level, mod(level, 175) + 1 from dual connect by level <= 175000
),
demographics (demographic, percentage, str) as (
            select 1, 40, '4%' from dual
  union all select 2, 30, '3%' from dual
  union all select 3, 30, '3%' from dual
  -- ...
  union all select 174, 2, '.02%' from dual
  union all select 175, 1, '.01%' from dual
)
-- actual query
select demographic, percentage, id, rn
from (
  select d.demographic, d.percentage, t.id,
    row_number() over (partition by d.demographic order by dbms_random.value) as rn
  from demographics d
  join my_table t on t.demographic = d.demographic
)
where rn <= 5 * percentage;

DEMOGRAPHIC PERCENTAGE         ID         RN
----------- ---------- ---------- ----------
          1         40      94150          1
          1         40      36925          2
          1         40     154000          3
          1         40      82425          4
...
          1         40     154350        199
          1         40     126175        200
          2         30      36051          1
          2         30       1051          2
          2         30     100451          3
          2         30      18026        149
          2         30     151726        150
          3         30     125302          1
          3         30     152252          2
          3         30     114452          3
...
          3         30     104652        149
          3         30      70527        150
        174          2      35698          1
        174          2      67548          2
        174          2     114798          3
...
        174          2      70698          9
        174          2      30973         10
        175          1     139649          1
        175          1     156974          2
        175          1     145774          3
        175          1      97124          4
        175          1      40074          5

with my_table (id, demographic) as (
  select level, mod(level, 175) + 1 from dual connect by level <= 175000
),
demographics (demographic, percentage, str) as (
            select 1, 40, '4%' from dual
  union all select 2, 30, '3%' from dual
  union all select 3, 30, '3%' from dual
  -- ...
  union all select 174, 2, '.02%' from dual
  union all select 175, 1, '.01%' from dual
)
select demographic, percentage, count(id) as ids, min(id) as min_id, max(id) as max_id
from (
  select d.demographic, d.percentage, t.id,
    row_number() over (partition by d.demographic order by dbms_random.value) as rn
  from demographics d
  join my_table t on t.demographic = d.demographic
)
where rn <= 5 * percentage
group by demographic, percentage
order by demographic;

DEMOGRAPHIC PERCENTAGE        IDS     MIN_ID     MAX_ID
----------- ---------- ---------- ---------- ----------
          1         40        200        175     174825
          2         30        150          1     174126
          3         30        150       2452     174477
        174          2         10      23448     146648
        175          1          5      19074     118649