BigQuery：除以列中值的总和以找到比率

Question

我有一个简单的表，有两列 Bin_name (int) 和 Count_in_this_bin (int)

我想将其转换为每个 bin 与所有 bin 中总计数的比率。

我在 Google BigQuery 中使用了以下查询：

SELECT count_in_bin/(SELECT SUM(count_in_bin) FROM [table])
FROM [table]

然后我得到

错误：查询失败 错误：SELECT 子句中不允许子选择

现在谁能告诉我在 BigQuery 中进行这种简单划分的正确方法？

Answer 1

BigQuery 旧版 SQL

#legacySQL
SELECT 
  count_in_bin, 
  RATIO_TO_REPORT(count_in_bin) OVER() AS ratio
FROM [project:dataset.table]

BigQuery 标准 SQL

#standardSQL
SELECT 
  count_in_bin, 
  count_in_bin / total AS ratio
FROM `project.dataset.table`, 
(SELECT SUM(count_in_bin) total FROM `project.dataset.table`)

Answer 2

您正在寻找窗口/分析函数。在标准 SQL 中，这将是：

SELECT count_in_bin / SUM(count_in_bin) OVER () 
FROM [table]

在旧版 SQL 中，您似乎需要一个子查询：

SELECT count_in_bin, count_in_bin / total_count_in_bin
FROM (SELECT count_in_bin, SUM(count_in_bin) OVER () as total_count_in_bin
      FROM [table]
     ) t