我已经从 MySQL 导入了一个表到 Hive,该表有 1000 万行,现在在 Impala 中执行一些操作以检查功能和性能。现在,当我发出以下查询时,出现错误 argument of type 'NoneType' is not iterable
。
select count(id) from my_table_name;
导入数据后我需要做些什么来解决这个问题吗?我打算主要将 Impala 用于分析目的,因此它涉及很多 SUM 和 COUNT 函数。
最佳答案
尝试使用 refresh
命令。
这是来自 Cloudera 文档的引用:
Syntax:
REFRESH [db_name.]table_name Usage notes:
Use the REFRESH statement to load the latest metastore metadata and block location data for a particular table in these scenarios:
After loading new data files into the HDFS data directory for the table. (Once you have set up an ETL pipeline to bring data into Impala on a regular basis, this is typically the most frequent reason why metadata needs to be refreshed.) After issuing ALTER TABLE, INSERT, LOAD DATA, or other table-modifying SQL statement in Hive.
关于sql - 黑斑羚 : argument of type 'NoneType' is not iterable,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/39242311/