BigQuery：使用交叉引用查询重复字段答案

【问题标题】：BigQuery: Querying Repeated Fields with Cross ReferenceBigQuery：使用交叉引用查询重复字段
【发布时间】：2018-07-04 13:46:10
【问题描述】：

我继承了一个具有某种特殊架构的 BigQuery 表：

[
  { "name":"hardware_id", "type":"STRING", "mode":"NULLABLE" },
  { "name":"manufacturer", "type":"STRING", "mode":"NULLABLE" },
  { "name":"model", "type":"STRING", "mode":"NULLABLE" },
  { "fields":[
    { "name":"brand", "type":"STRING", "mode":"REPEATED" },
    { "name":"model_name", "type":"STRING", "mode":"NULLABLE" }
  ], "name":"components", "type":"RECORD", "mode":"REPEATED" },
  { "name":"ram", "type":"INTEGER", "mode":"NULLABLE" },
  { "name":"hdd", "type":"INTEGER", "mode":"NULLABLE" }
]

数据的结构如下：

hw_id | manufacturer | model | components.type | components.model_name | ram |  hdd
------+--------------+-------+-----------------+-----------------------+-----+-----
    1 |       Lenovo |   ABX |             GPU |           Radeon 5500 |  16 | 1000
      |              |       |             CPU |               Core i7 |     |
      |              |       | SCSI Controller |          Adaptec 2940 |     |
------+--------------+-------+-----------------+-----------------------+-----+-----
    2 |         Dell |   ZXV |             CPU |               Core i7 |   4 |  500
      |              |       |             GPU |               GeForce |     |
      |              |       |           Sound |          SoundBlaster |     |
------+--------------+-------+-----------------+-----------------------+-----+-----
    3 |          IBM |  PS/2 |             CPU |                  i386 |   1 |  100
      |              |       |           Sound |          SoundBlaster |     |
      |              |       |             GPU |               GeForce |     |

我想一次查询多个组件，例如找到所有具有 Core i7 CPU 和 SoundBlaster 声卡的硬件。不幸的是，“组件”字段的顺序不一致，“型号名称”可能会产生歧义，因此我还需要查询对应的“品牌”字段。

我可以为单个组件创建查询，但还不能同时为多个组件创建查询。你能提示我正确的方向吗？

【问题讨论】：

标签： sql google-cloud-platform google-bigquery

【解决方案1】：

以下是 BigQuery 标准 SQL

#standardSQL
SELECT *
FROM `project.dataset.table`
WHERE 2 = 
  (SELECT COUNT(1) 
    FROM UNNEST(components) 
    WHERE (type, model_name) IN (
      ('Sound', 'SoundBlaster'), ('CPU', 'Core i7')
    )
  )

您可以使用您问题中的虚拟数据进行测试，如下所示

#standardSQL
WITH `project.dataset.table` AS (
  SELECT 1 hw_id, 'Lenovo' manufacturer, 'ABX' model, [STRUCT<type STRING, model_name STRING>('GPU', 'Radeon 5500'), ('CPU', 'Core i7'), ('SCSI Controller', 'Adaptec 2940')] components, 16 ram, 1000 hdd UNION ALL
  SELECT 2, 'Dell', 'ZXV', [('CPU', 'Core i7'), ('GPU', 'GeForce'), ('Sound', 'SoundBlaster')], 4, 500 UNION ALL
  SELECT 3, 'IBM', 'PS/2', [('CPU', 'i386'), ('Sound', 'SoundBlaster'), ('GPU', 'GeForce')], 1, 100 
)
SELECT *
FROM `project.dataset.table`
WHERE 2 = 
  (SELECT COUNT(1) 
    FROM UNNEST(components) 
    WHERE (type, model_name) IN (
      ('Sound', 'SoundBlaster'), ('CPU', 'Core i7')
    )
  )

所以结果将是

hw_id | manufacturer | model | components.type | components.model_name | ram |  hdd
------+--------------+-------+-----------------+-----------------------+-----+-----
    2 |         Dell |   ZXV |             CPU |               Core i7 |   4 |  500
      |              |       |             GPU |               GeForce |     |
      |              |       |           Sound |          SoundBlaster |     |

【讨论】：