无法将 BigQuery 遗留 SQL 转换为标准 SQL 以用于 HAVING LEFT(...)

Question

我想使用 BigQuery Standard SQL for a query like this one:

SELECT package, COUNT(*) count
FROM (
  SELECT REGEXP_EXTRACT(line, r' ([a-z0-9\._]*)\.') package, id
  FROM (
    SELECT SPLIT(content, '\n') line, id
    FROM [github-groovy-files:github.contents] 
    WHERE content CONTAINS 'import'
    HAVING LEFT(line, 6)='import' )
    GROUP BY package, id
  )
GROUP BY 1
ORDER BY count DESC
LIMIT 30;

我无法通过这样的事情（有效但不能分组或计数）：

with lines as 
(SELECT SPLIT(c.content, '\n') line, c.id as id
      FROM `<dataset>.contents` c, `<dataset>.files` f 
      WHERE c.id = f.id AND f.path LIKE '%.groovy')
select 
  array(select REGEXP_REPLACE(l, r'import |;', '') AS class from unnest(line) as l where l like 'import %') imports, id
from lines;

LEFT() 不在标准 SQL 中，似乎没有接受数组类型的函数。

Answer 1

LEFT() is not in Standard SQL ...

在 BigQuery Standard SQL 中，您可以使用 SUBSTR(value, position[, length]) 而不是 Legacy 的 LEFT

... and there doesn't seem to be a function that will accept and array type.

有很多 Array's related functions as well as functions that accept array as argument - for example UNNEST()

I would like to use BigQuery Standard SQL for a query like this one:

以下是 BigQuery 标准的等效查询 SQL

SELECT package, COUNT(*) COUNT
FROM (
  SELECT REGEXP_EXTRACT(line, r' ([a-z0-9\._]*)\.') package, id
  FROM (
    SELECT line, id
    FROM `github-groovy-files.github.contents`,
    UNNEST(SPLIT(content, '\n')) line
    WHERE SUBSTR(line, 1, 6)='import' 
  )
  GROUP BY package, id
)
GROUP BY 1
ORDER BY COUNT DESC
LIMIT 30

您可以使用 WHERE line LIKE 'import%'

而不是 WHERE SUBSTR(line, 1, 6)='import'

另请注意，此查询可以用多种方式编写 - 因此在我上面的示例中，我专注于 "translating" 您的查询从遗留到标准 sql，同时保留核心结构和方法原始查询

但是如果你想用标准的力量重写它 SQL - 你最终会得到类似下面的东西

SELECT REGEXP_EXTRACT(line, r' ([a-z0-9\._]*)\.') package, COUNT(DISTINCT id) count
FROM `github-groovy-files.github.contents`,
UNNEST(SPLIT(content, '\n')) line
WHERE line LIKE 'import%' 
GROUP BY 1
ORDER BY count DESC
LIMIT 30

无法将 BigQuery 遗留 SQL 转换为标准 SQL 以用于 HAVING LEFT(...)

Unable to translate BigQuery legacy SQL to standard SQL for HAVING LEFT(...)

google-bigquery

bigquery-standard-sql