Question

目前正在使用谷歌的BigQuery。我的遗留查询如下：

Select * FROM FLATTEN(FLATTEN([DB.table1], record.atr), record.atr.value) 
WHERE record.atr.value IN "1"

我理解BigQuery now automatically flattens表格，所以我认为这样可以解决问题：

SELECT * FROM `DB.table1`
WHERE record.atr.value IN "1"

但是我收到错误错误：无法访问类型为ARRAY，sv ARRAY，...＆gt;＆gt;的值的字段值在[2:17]

如何将此转换为标准SQL查询？

Answer 1

使用标准SQL时，BigQuery不会自动压缩数组;您提供的链接表示相反。在您的情况下，查询将是这样的：

#standardSQL
SELECT * EXCEPT(value), value
FROM `Db.table1`
CROSS JOIN UNNEST(record.atr) AS atr
CROSS JOIN UNNEST(atr.value) AS value;

如果您想为空数组获取一行，则可以改为使用LEFT JOIN：

#standardSQL
SELECT * EXCEPT(value), value
FROM `Db.table1`
LEFT JOIN UNNEST(record.atr) AS atr
LEFT JOIN UNNEST(atr.value) AS value;

以下是您可以尝试运行的示例查询：

#standardSQL
WITH Input AS (
  SELECT STRUCT(ARRAY<STRUCT<x STRING, value ARRAY<INT64>>>[('foo', [1, 2]), ('bar', [3, 4, 5])] AS atr) AS record UNION ALL
  SELECT STRUCT(ARRAY<STRUCT<x STRING, value ARRAY<INT64>>>[('baz', [6, 7])])
)
SELECT * EXCEPT (value)
FROM Input
CROSS JOIN UNNEST(record.atr) AS atr
CROSS JOIN UNNEST(atr.value) AS value;

Answer 2

如何将其转换为标准SQL查询？   SELECT * FROM`DB.table1`
  WHERE record.atr.value IN＆＃34; 1＆＃34;

以下是BigQuery Standard SQL

#standardSQL
SELECT *
FROM `DB.table1`
WHERE (SELECT COUNT(1) 
        FROM UNNEST(record.atr) AS atr, 
              UNNEST(atr.value) AS val 
        WHERE val IN ('1')) > 0

您可以使用虚拟数据进行测试（部分借鉴了Elliott的例子）

#standardSQL
WITH `DB.table1` AS (
  SELECT 1 AS id, STRUCT([STRUCT<x STRING, value ARRAY<STRING>>('foo', ['1', '2']), ('bar', ['3', '4', '5'])] AS atr) AS record UNION ALL
  SELECT 2, STRUCT([STRUCT<x STRING, value ARRAY<STRING>>('baz', ['6', '7'])])
)
SELECT *
FROM `DB.table1`
WHERE (SELECT COUNT(1) 
        FROM UNNEST(record.atr) AS atr, 
              UNNEST(atr.value) AS val 
        WHERE val IN ('1')) > 0

如何将嵌套展平转换为标准SQL

2 个答案: