Question

今天我尝试在Web编辑器UI中使用标准SQL语言编写UDF，并且我已经取消选中“使用旧版SQL”选项，但它返回给我以下错误消息：未实现：您不能将旧版SQL UDF与标准SQL查询一起使用。请参阅https://cloud.google.com/bigquery/docs/reference/standard-sql/migrating-from-legacy-sql#differences_in_user-defined_javascript_functions

因此，我尝试了在Google云平台上提供的外部UDF示例：https://cloud.google.com/bigquery/docs/reference/standard-sql/user-defined-functions。但它仍然向我返回相同的错误消息。在下面的示例中：

CREATE TEMPORARY FUNCTION multiplyInputs(x FLOAT64, y FLOAT64)
RETURNS FLOAT64
LANGUAGE js AS """
  return x*y;
""";
WITH numbers AS
  (SELECT 1 AS x, 5 as y
  UNION ALL
  SELECT 2 AS x, 10 as y
  UNION ALL
  SELECT 3 as x, 15 as y)
SELECT x, y, multiplyInputs(x, y) as product
FROM numbers;

问题：如何在Web UI中将标准SQL与外部UDF一起使用？

Answer 1

确保不在＆＃34; UDF编辑器中输入输入＆＃34;面板。它应该与您的查询的其余部分一起使用。有关示例，请参阅the topic in the migration guide：

#standardSQL
-- Computes the harmonic mean of the elements in 'arr'.
-- The harmonic mean of x_1, x_2, ..., x_n can be expressed as:
--   n / ((1 / x_1) + (1 / x_2) + ... + (1 / x_n))
CREATE TEMPORARY FUNCTION HarmonicMean(arr ARRAY<FLOAT64>)
  RETURNS FLOAT64 LANGUAGE js AS """
var sum_of_reciprocals = 0;
for (var i = 0; i < arr.length; ++i) {
  sum_of_reciprocals += 1 / arr[i];
}
return arr.length / sum_of_reciprocals;
""";

WITH T AS (
  SELECT GENERATE_ARRAY(1.0, x * 4, x) AS arr
  FROM UNNEST([1, 2, 3, 4, 5]) AS x
)
SELECT arr, HarmonicMean(arr) AS h_mean
FROM T;

BigQuery：带有标准SQL的外部UDF

1 个答案: