external_table()external_table()

按名称引用外部表。References an external table by name.

external_table('StormEvent')

备注

  • external_table 函数与 table 函数具有类似的限制。The external_table function has similar restrictions as the table function.
  • 标准查询限制还适用于外部表查询。Standard query limits apply to external table queries as well.

语法Syntax

external_table ( TableName [, MappingName ] )external_table ( TableName [, MappingName ] )

参数Arguments

  • TableName：正在查询的外部表的名称。TableName : The name of the external table being queried. 必须是引用 blob、adl 或 sql 类型的外部表的字符串文本。Must be a string literal referencing an external table of kind blob, adl or sql.

  • MappingName ：映射对象的可选名称，该对象将实际（外部）数据分片中的字段映射到此函数输出的列。MappingName : An optional name of the mapping object that maps the fields in the actual (external) data shards to the columns output by this function.

后续步骤Next steps