sql - 如何在 Snowsql GroupBy 中组合数组并只保留不同的值？

Question

我正在尝试运行一个查询，列出用户为我的数据集提交的所有不同市场。市场列中的值已经是数组格式。当我运行下面的查询时，我得到一个数组数组，并且某些市场可能会被多次列出，因为 distinct 子句查看的是唯一数组而不是数组中的值。例如，如果我尝试将 ['New York'] 和 ['New York' , 'Chicago'] 分组，我的目标是获得 ['New York', 'Chicago'] 作为我的结果，但目前正在[['纽约']，['纽约'，'芝加哥']]。感谢任何帮助。

SELECT 
  s.submitter_id,
  ARRAY_AGG(DISTINCT s.markets)
FROM 
  analytics.submissions AS s
GROUP BY 1

Answer 1

一个简单的方法是先将数组展平

WITH data AS (
 SELECT submitter_id, split(markets,';') AS markets 
 FROM VALUES (1,'new york'), (1,'new york;chicargo') s(submitter_id, markets)
)
SELECT 
  a.submitter_id,
  ARRAY_AGG(DISTINCT a.market)
FROM (
    SELECT s.submitter_id
        ,f.value AS market
    FROM data AS s,
    LATERAL FLATTEN(input => s.markets) f
) AS a
GROUP BY 1;

Answer 2

使用 javascript UDF 的变体：

WITH data AS (
 SELECT submitter_id, split(markets,';') AS markets 
 FROM VALUES (1,'new york'), (1,'new york;chicargo') s(submitter_id, markets)
)
SELECT 
  submitter_id,
  array_flat_distinct(ARRAY_AGG(distinct markets))
from data
group by 1;

其中UDF定义为：

create or replace function array_flat_distinct("a" array)
returns array
language javascript
as
$$
    return [...new Set(a.reduce((b,c)=>[...b,...c]))]
$$
;