Question

我正在尝试将以下druid sql查询转换为druid json查询，因为我拥有的其中一列是多值维度，因此druid不支持sql样式查询。

我的SQL查询：

SELECT date_dt, source, type_labels, COUNT(DISTINCT unique_p_hll)
  FROM "test"
WHERE 
  type_labels = 'z' AND
  (a_id IN ('a', 'b', 'c') OR b_id IN ('m', 'n', 'p'))
GROUP BY date_dt, source, type_labels;

unique_p_hll是具有唯一性的hll列。

我想出的druid json查询如下：

{
  "queryType": "groupBy",
  "dataSource": "test",
  "granularity": "day",
  "dimensions": ["source", "type_labels"],
  "limitSpec": {},
  "filter": {
    "type": "and",
    "fields": [
      { "type": "selector", "dimension": "type_labels", "value": "z" },   
      { "type": "or", "fields": [
        { "type": "in", "dimension": "a_id", "values": ["a", "b", "c"] },
        { "type": "in", "dimension": "b_id", "values": ["m", "n", "p"] }
      ]}
    ]
  },
  "aggregations": [
    { "type": "longSum", "name": "unique_p_hll", "fieldName": "p_id" }
  ],
  "intervals": [ "2018-08-01/2018-08-02" ]
}

但是json查询似乎返回空结果集。我可以在Pivot UI中正确看到输出。尽管数组列type_labels的值显示为{"array_element": "z"}而不是简单的"z"。

Answer 1

查询返回空字符串，还是返回零记录的格式化JSON？

如果是前者，我可以建议一些线索来调试此问题：

确保查询已正确发送到代理，如Druid's query tutorial所示：

curl -X 'POST' -H 'Content-Type:application/json' -d @query-file.json http://<BROKER-IP>:<BROKER-PORT>/druid/v2?pretty

此外，请检查Broker的日志中是否有错误。

Apache Druid SQL查询转换为基于JSON的查询

1 个答案: