event_dimを引数に取ってゴニョゴニョするUDFを書きたいんだけど型不一致で怒られて動かないよ、というお話

firebase analytics udfお試し.sql

CREATE TEMP FUNCTION
  hoge(event
    STRUCT<
      name STRING,
      params ARRAY<
        STRUCT<
          key STRING,
          value STRUCT<string_value STRING, int_value INT64, float_value FLOAT64, double_value FLOAT64>
        >
      >,
      timestamp_micros INT64,
      previous_timestamp_micors INT64,
      date STRING
    >
  )
  RETURNS ARRAY <STRUCT<message string,
  path string>>
  LANGUAGE js AS """
  var result = [];
      for (var i in event.params) {
          result.push({message: event.params[i].key, path: i});
      }
  return result;
""";

CREATE TEMP FUNCTION
  getErrors(events
  ARRAY <
    STRUCT<
      name STRING,
      params ARRAY<
        STRUCT<
          key STRING,
          value STRUCT<string_value STRING, int_value INT64, float_value FLOAT64, double_value FLOAT64>
        >
      >,
      timestamp_micros INT64,
      previous_timestamp_micors INT64,
      date STRING
    >
  >
  )
  RETURNS ARRAY <STRUCT<message string,
  path string>>
   AS (ARRAY(SELECT STRUCT('ss' AS message, '22' AS path)));

SELECT
  user_dim.user_id,
  ARRAY(select event_dim[offset(0)])  e0
,  hoge(event_dim[offset(0)]) e1
, event_dim
,  getErrors(event_dim) e21
--,  getErrors(ARRAY(select event_dim[offset(0)])) e2
FROM
  `firebase-analytics-sample-data.android_dataset.app_events_20160607` 
LIMIT
  10