Question

有谁知道如何：

Unnest一个postgres数组创建一个新数组作为＆＃34;选择不同的＆＃34;从那个unnested数组（所以没有元素重复）让新数组按照以前的方式排序？

实施例

我有以下3列：

order_id, channel_path, hit_timestamp_path
    x      a,b,b,c,d      1,2,3,4,5
    y      q,w,e,r,r      2,3,4,5,6
    .
    .
    .

我想最终得到以下结论：

order_id, channel_path
    x      a,b,c,d      
    y      q,w,e,r   
    .
    .
    .

问题是我这样做的方式，我最终会得到这样的结果：

order_id, channel_path
    x      b,a,c,d      
    y      w,r,e,q   
    .
    .
    .

我正在尝试的初始解决方案如下：

SELECT order_id, (
                  SELECT array_agg(unnested_channels)
                  FROM (
                        SELECT DISTINCT unnested_channels
                        FROM (
                              SELECT unnest(channel_path) AS unnested_channels,
                                     unnest(hit_timestamp_path) as unnested_timestamps
                                     order by 2 asc
                              ) AS unnested_channels_table
                       ) AS distinct_unnested_channels_table
                  ) AS distinct_channel_path
from dim_conversion_path;

Answer 1

这样的事情：

select order_id, array_agg(x order by rn) as unique_channel_path
from (
  select distinct on (order_id, a.x) order_id, a.x, a.rn
  from dim_conversion_path, unnest(channel_path) with ordinality as a (x,rn)
  order by 1,2,3  
) t
group by order_id

在PostgreSQL中创建一个有组织的不同元素数组

1 个答案: