Athena - 如何通过嵌套的 json 值查询？

Question

在 Athena 中，我们试图获取所有含有种子的水果。我们面临的问题是种子 true/false 嵌套在 json 中，我们似乎无法在 WHERE 子句中对其进行过滤。我们只能在嵌套的 json 路径中将 SELECT 它作为 hasSeeds 时看到结果，但这会返回所有种子结果 true 和 false 而不仅仅是 true

-- This returns all seeds, but we want to filter in the WHERE clause by hasSeeds true
SELECT foodId, foodType, json_extract(payload,'$.food.info.seeds') AS hasSeeds
FROM "food_table"
WHERE foodType = 'fruit'

-- 3 attempts to filter by nested json value seeds true (not working)
SELECT * FROM
(SELECT foodId, foodType, json_extract(payload,'$.food.info.seeds') AS hasSeeds
FROM "food_table"
WHERE foodType = 'fruit')
WHERE hasSeeds = true

SELECT foodId, foodType, json_extract(payload,'$.food.info.seeds') AS hasSeeds
FROM "food_table"
WHERE foodType = 'fruit' and hasSeeds = true

SELECT foodId, foodType, json_extract(payload,'$.food.info.seeds') AS hasSeeds
FROM "food_table"
WHERE foodType = 'fruit' and json_extract(payload,'$.food.info.seeds') = true

知道如何在嵌套 json 上按 hasSeeds true 过滤时让查询按预期工作吗？

使用 JSON 结构更新：

{
  "foodId": 1,
  "foodType": "fruit",
  "payload": {
    "food": {
      "name": "apple",
      "info": {
        "seeds": true,
        "calories": 95
      }
    }
  }
}

{
  "foodId": 2,
  "foodType": "fruit",
  "payload": {
    "food": {
      "name": "banana"
    }
  }
}

{
  "foodId": 3,
  "foodType": "vegetable",
  "payload": {
  }
}

{
  "foodId": 4,
  "foodType": "fruit",
  "payload": {
  }
}

尝试了这个查询，但返回的结果不正确：

WITH dataset(jsn) AS (
    values (JSON '{"payload":{"food":{"info":{"seeds":true}}}}')
)

SELECT foodId, foodType, json_extract(payload,'$.food.info.seeds') AS hasSeeds, jsn
FROM "food_table", dataset
WHERE cast(json_extract_scalar(jsn, '$.payload.food.info.seeds') AS BOOLEAN) = true

基本上，hasSeeds 返回为 true，这是正确的，但其他食品，例如那些缺少有效载荷的孩子的食品仍然使用 jsn 字段返回，而不是实际上仅通过类似的方式仅查询 WHERE 子句payload.food.info.seeds = true

知道怎么解决吗？

Answer 1

假设你有下一个json结构，你需要使用json_extract_scalar:

WITH dataset(jsn) AS (
    values (JSON '{"food":{"info":{"seeds":true}}}')
)

SELECT *
FROM dataset
WHERE cast(json_extract_scalar(jsn, '$.food.info.seeds') AS BOOLEAN) = true

UPD

基于提供的 json WHERE 子句应该类似于：

WHERE try(cast(json_extract_scalar(payload, '$.payload.food.info.seeds') AS BOOLEAN)) = true