如何将参数传递给colab上的bigquery查询

Question

我在 colab 上有一个 Bigquery 查询：

from google.colab import auth
auth.authenticate_user()
print('Authenticated')
project_id = '[your project ID]'

sample_count = 2000
df = pd.io.gbq.read_gbq('''
  SELECT name, SUM(number) as count
  FROM `bigquery-public-data.usa_names.usa_1910_2013`
  WHERE state = 'TX'
  AND year BETWEEN 1910 AND 1920
  GROUP BY name
  ORDER BY count DESC
  LIMIT 100
''', project_id=project_id, dialect='standard')

df.head()

它有效，但现在我尝试将一个参数传递到查询中并替换查询 WHERE 子句中的“1920”。此参数依赖于另一个文件

end_year = max(record.year) # set end_year

df = pd.io.gbq.read_gbq('''
  SELECT name, SUM(number) as count
  FROM `bigquery-public-data.usa_names.usa_1910_2013`
  WHERE state = 'TX'
  AND year BETWEEN 1910 AND end_year
  GROUP BY name
  ORDER BY count DESC
  LIMIT 100
''', project_id=project_id, dialect='standard')

df.head()

但是我得到一个错误：

BadRequest: 400 Syntax error: Unexpected identifier "end_year"

我猜参数没有成功传递到查询中，但我不知道如何解决它。

Answer 1

就 python 而言，您传递给 bigquery 的查询是一个字符串，因此它无法调用您的变量。

像这样：

end_year = max(record.year) # set end_year

df = pd.io.gbq.read_gbq('''
  SELECT name, SUM(number) as count
  FROM `bigquery-public-data.usa_names.usa_1910_2013`
  WHERE state = 'TX'
  AND year BETWEEN 1910 AND %s
  GROUP BY name
  ORDER BY count DESC
  LIMIT 100
''' % (end_year), project_id=project_id, dialect='standard')

df.head()

此处非常重要的说明——我假设这是您个人运行用于一次性数据分析的脚本，而不是用于 SQL 注入的生产应用程序中的代码可能是个问题。

Answer 2

正如@Mike Karp 所提到的，您代码中的查询是一个字符串，这就是当您将变量直接传递给查询时遇到错误的原因。

您也可以使用 python 的 f string 来格式化您的字符串并能够在您的查询中传递变量。

from google.colab import auth
import pandas as pd
auth.authenticate_user()
print('Authenticated')
project_id = 'PROJECT_ID'

end_year = max(record.year) # set end_year

query = (f" SELECT name, SUM(number) as count \
  FROM `bigquery-public-data.usa_names.usa_1910_2013` \
  WHERE state = 'TX' \
  AND year BETWEEN 1910 AND {end_year} \
   GROUP BY name \
  ORDER BY count DESC \
  LIMIT 100")

df = pd.io.gbq.read_gbq(query=query, project_id=project_id, dialect='standard')

df.head()

如何将参数传递给colab上的bigquery查询

How to pass a parameter into bigquery query on colab

python

sql

google-bigquery

google-colaboratory