如何从雪花中的变体列创建子集？

Question

例如，假设我的变量列“xyz”包含如下数据：

{
  "post_new_visits": "Repeat",
  "post_new1_week": "Thursday",
  "post_new2_appt": "Weekday",
  "post_new3_site": "12:50AM",
  "post_new4_channel": "5.0",
  "pre_new2_appt": "Weekday",
  "pre_new3_site": "12:50AM",
  "pre_new4_channel": "5.0"
}

我想从上面的变量列中创建一个新的变量列，它应该只有“post*”键值，如下所示，输出应该是这样的。

{
  "post_new_visits": "Repeat",
  "post_new1_week": "Thursday",
  "post_new2_appt": "Weekday",
  "post_new3_site": "12:50AM",
  "post_new4_channel": "5.0",
}

有什么办法可以实现吗？

Answer 1

也许您可以展平并重新构建 JSON。例如：

create table tmp ( v variant )
as 
select
    parse_json(
        '{  "post_new_visits": "Repeat",
          "post_new1_week": "Thursday",
          "post_new2_appt": "Weekday",
          "post_new3_site": "12:50AM",
          "post_new4_channel": "5.0",
          "pre_new2_appt": "Weekday",
          "pre_new3_site": "12:50AM",
          "pre_new4_channel": "5.0"}'
    )
union all                              
select
    parse_json(
        '{  "post_new_visits": "New",
          "post_new1_week": "Friday",
          "post_new2_appt": "Weekday",
          "post_new3_site": "13:50AM",
          "post_new4_channel": "4.0",
          "pre_new2_appt": "Weekday",
          "pre_new3_site": "14:50AM",
          "pre_new4_channel": "2.0"}'
    );                                      




select
    OBJECT_AGG(v2.key, v2.value)
from
    tmp,
    lateral flatten(input => v) v2
where
    v2.key like 'post%'
group by
    v2.seq;