解析 Snowflake 中的 JSON 列表 - 将 redshift sql 转换为 Snowflake sql

Question

我有一些 Redshift SQL，我正在尝试将其转换为雪花 SQL 以从 json 字段中提取值。我遇到的问题是所需索引的规范。

因为我运行 A/B/n 测试，所以最多可以有多个索引“n”。

所以我让这段 SQL 适用于 Redshift：

SELECT JSON_EXTRACT_PATH_TEXT(json_extract_array_element_text (e.splits,n.n),'split_type') types
     , JSON_EXTRACT_PATH_TEXT(json_extract_array_element_text (e.splits,n.n),'weight') as weight
FROM experiments e, (SELECT  (p0.n + p1.n*2 + p2.n * POWER(2,2) + p3.n * POWER(2,3) + p4.n * POWER(2,4) + p5.n * POWER(2,5)
                              + p6.n * POWER(2,6) + p7.n * POWER(2,7) + p8.n * POWER(2,8) + p9.n * POWER(2,9))::int as n
                     FROM
                         (SELECT 0 as n UNION SELECT 1) p0,
                         (SELECT 0 as n UNION SELECT 1) p1,
                         (SELECT 0 as n UNION SELECT 1) p2,
                         (SELECT 0 as n UNION SELECT 1) p3,
                         (SELECT 0 as n UNION SELECT 1) p4,
                         (SELECT 0 as n UNION SELECT 1) p5,
                         (SELECT 0 as n UNION SELECT 1) p6,
                         (SELECT 0 as n UNION SELECT 1) p7,
                         (SELECT 0 as n UNION SELECT 1) p8,
                         (SELECT 0 as n UNION SELECT 1) p9
                     Order by 1
                     ) n
WHERE types <> ''
AND weight <> ''

从阅读 Snowlfake 的文档来看，以下内容似乎应该有效：

SELECT parse_json(parse_json(e.splits)[n.n]):split_type as types,
       parse_json(parse_json(e.splits)[n.n]):weight as weight
FROM experiments e, (SELECT (p0.n ...

但是我收到错误“SQL 编译错误：错误第 1 行位于位置 39 无效标识符‘NN’”

我想知道是否有人可以帮助解决这个问题？

编辑：

实验表如下所示：

exp_ID | splits
1  | [{"id":203,"weight":50,"split_type":"a"},{"id":204,"weight":50,"split_type":"control"}]
2  | [{"id":205,"weight":33.33,"split_type":"a"},{"id":206,"weight":33.33,"split_type":"b"},{"id":207,"weight":33.33,"split_type":"c"}]
3  | [{"id":208,"weight":25,"split_type":"a"},{"id":209,"weight":25,"split_type":"b"},{"id":210,"weight":25,"split_type":"c"},{"id":211,"weight":25,"split_type":"d"}]

所需输出：

exp_ID | ID  | types   | weight
1      | 203 | a       | 50
1      | 204 | control | 50
2      | 205 | a       | 33.33
2      | 206 | b       | 33.33
2      | 207 | c       | 33.33
3      | 208 | a       | 25
3      | 209 | b       | 25
3      | 210 | c       | 25
3      | 211 | d       | 25

Answer 1

下面的文章将演示使用 LATERAL Flatten 从 JSON 文档中提取信息的各种示例。提供了与 GET_PATH、UNPIVOT 和 SEQ 函数一起使用的示例。

https://community.snowflake.com/s/article/Dynamically-extracting-JSON-using-LATERAL-FLATTEN