GCP 存储过程访问嵌套列并执行计算

Question

有没有办法创建一个过程来解析具有嵌套字段的列，以便对所有列（甚至是嵌套列）执行计算？

我的问题是这个过程停留在第一级，只在那里执行我的计算，而不动态解析我的嵌套列。

CREATE OR REPLACE PROCEDURE `myprocedurename`(
   _tableName STRING,
   _destination STRING
)
BEGIN
  DECLARE _columns STRING;
  DECLARE _sql STRING;

  SET _columns = (
    SELECT STRING_AGG(
      CASE
        WHEN field_path = column_name THEN CONCAT("ROUND(COUNTIF(", column_name, " IS NOT NULL) * 100.0 / COUNT(*), 2) AS completude_", column_name) -- Handle top-level columns
        ELSE CONCAT("ROUND(COUNTIF(", REPLACE(field_path, '.', '_'), " IS NOT NULL) * 100.0 / COUNT(*), 2) AS completude_", REPLACE(field_path, '.', '_')) -- Handle nested fields (but it takes into consideration only the top level of the nested columns)
      END, ', ')
    FROM `myproject.INFORMATION_SCHEMA.COLUMN_FIELD_PATHS`
    WHERE table_name = _tableName);

  SET _sql = CONCAT("CREATE OR REPLACE TABLE `mydataset.", _destination, "` AS SELECT ", _columns, " FROM `mydataset.", _tableName, "`");

  EXECUTE IMMEDIATE _sql;
END;