如何使用 apache Drill 展平两个 json 数组答案

【问题标题】：How to flatten two json arrays using apache drill如何使用 apache Drill 展平两个 json 数组
【发布时间】：2017-12-19 07:55:29
【问题描述】：

{
    "id": "0001",
    "type": "donut",
    "name": "Cake",
    "ppu": 0.55,
    "batters":
        {
            "batter":
                [
                    { "id": "1001", "type": "Regular" },
                    { "id": "1002", "type": "Chocolate" },
                    { "id": "1003", "type": "Blueberry" },
                    { "id": "1004", "type": "Devil's Food" }
                ]
        },
    "topping":
        [
            { "id": "5001", "type": "None" },
            { "id": "5002", "type": "Glazed" },
            { "id": "5005", "type": "Sugar" },
            { "id": "5007", "type": "Powdered Sugar" },
            { "id": "5006", "type": "Chocolate with Sprinkles" },
            { "id": "5003", "type": "Chocolate" },
            { "id": "5004", "type": "Maple" }
        ]
}

我有上面的 json，我想同时展平 batter 和 topping 数组。

所以我试着做：

SELECT flatten(topping) as toping,flatten(batters.batter) as bat  FROM json.jsonfiles.`batter.json`;

这给了我

org.apache.drill.common.exceptions.UserRemoteException：验证错误：从第 1 行第 43 列到第 1 行第 49 列：表“击球手” 未找到 SQL 查询 null [错误 ID： 33cf80f2-f283-4401-90ce-c262474e0778 on acer:31010]

我该如何解决这个问题？我们可以在一个查询中展平两个数组吗？

【问题讨论】：

标签： apache-drill

【解决方案1】：

您需要添加表别名并在列中引用它。以下查询适用于您提供的示例数据。

SELECT flatten(a.topping) as toping,flatten(a.batters.batter) as bat  FROM  dfs.tmp.`batter.json` a;

【讨论】：