如何将雪花 table 转换为不同的结构

Question

id	name	DESCRIPTION	ACTIVE	UPDATED_JSON
id1	name-1	desc-1	true	{"diffFields": [{"fieldName": "name","valueAfter": "new-segment-name-1","valueBefore": null},{"fieldName": "active","valueAfter": true,"valueBefore": null}],"segmentId": "b204c220-ea8d-4cf4-b579-30eb59a1a2a4"}
id2	name-2	desc-2	true	{"diffFields": [{"fieldName": "name","valueAfter": "new-segment-name-2","valueBefore": null},{"fieldName": "active","valueAfter": true,"valueBefore": null}],"segmentId": "b204c220-ea8d-4cf4-b579-30eb59a1a2a4"}

我在snowflake中有一个table的上述结构。 UPDATED_JSON 是变体列。我想将此 table 更改为具有类似于下面的结构。在 UPDATED_JSON 中，我有 fieldName，当它的值为 name 时，我需要更新 name 列以包含 valueAfter 数据。 diffFields 未订购。如果 updated_json 中的 name 不存在，我想保留 name 列的当前值。

在下面的示例中，name-1 更改为 new-segment-name-1 因为 UPDATED_JSON 有一个 fieldName 的值为 name 和 valueAfter 的值为new-segment-name-1

id	name	DESCRIPTION	ACTIVE
id1	new-segment-name-1	desc-1	true
id2	new-segment-name-2	desc-2	true

我正在尝试使用 dbt

Answer 1

您的 CTE 数据：

WITH data(id, name, DESCRIPTION, ACTIVE, UPDATED_JSON) as (
    select column1, column2, column3, column4, parse_json(column5) from values    
    ('id1', 'name-1', 'desc-1', true,'{"diffFields": [{"fieldName": "name","valueAfter": "new-segment-name-1","valueBefore": null},{"fieldName": "active","valueAfter": true,"valueBefore": null}],"segmentId": "b204c220-ea8d-4cf4-b579-30eb59a1a2a4"}'),
   ('id2', 'name-2', 'desc-2', true, '{"diffFields": [{"fieldName": "name","valueAfter": "new-segment-name-2","valueBefore": null},{"fieldName": "active","valueAfter": true,"valueBefore": null}],"segmentId": "b204c220-ea8d-4cf4-b579-30eb59a1a2a4"}')
)

select id
    ,max(iff(f.value:fieldName::text = 'name', f.value:valueAfter::text, null))  as name
    ,DESCRIPTION
    ,active
from data, table(flatten(input=>UPDATED_JSON:diffFields)) f
group by 1,3,4;

给出：

ID	NAME	DESCRIPTION	ACTIVE
id2	new-segment-name-2	desc-2	TRUE
id1	new-segment-name-1	desc-1	TRUE

如何将雪花 table 转换为不同的结构

how to convert snowflake table to different structure

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