lateral view explode(decisionResults) p as decisionResults 切分数组对不对
时间: 2024-04-04 12:36:10 浏览: 19
这是一个Presto SQL语句中的操作,它会将数组类型的 `decisionResults` 列进行切分,生成多行数据,每行数据包含数组中的一个元素和该元素在数组中的位置。其中 `lateral view explode` 是 Presto SQL 中用于操作数组或 map 类型的关键词,它会将数组或 map 中的每个元素扩展为一行数据。 `p` 是扩展后的新别名,`decisionResults` 是原始列名。因此这个操作是正确的。
相关问题
lateral view explode
Lateral view explode is a feature in Hive, a data warehouse infrastructure built on top of Hadoop. It allows you to explode complex data structures such as arrays or maps into multiple rows. This can be useful when you want to unnest nested data and process it in a tabular format.
For example, let's say you have a table with a column that contains an array of values. By using lateral view explode, you can transform each element of the array into a separate row, repeating the other columns for each exploded value.
Here's an example query:
```
SELECT col1, exploded_value
FROM my_table
LATERAL VIEW explode(array_column) explodedTable AS exploded_value;
```
In this query, `my_table` is the table name, `col1` is a column from the table, and `array_column` is the column containing the array. The lateral view explode function unnests the array, and each exploded value is assigned to the alias `exploded_value`.
LATERAL VIEW explode
LATERAL VIEW explode是Hive中的一个操作符,用于将数组类型的列拆分成多行,每行包含原始表中的一行以及数组中的一个元素。例如,假设有一个名为array_col的数组列,包含三个元素[1,2,3],那么使用LATERAL VIEW explode(array_col)操作符后,会生成三个行,每行包含原始表中的一行以及数组中的一个元素,即(1),(2),(3)。LATERAL VIEW explode操作符在使用Hive中内置的UDTF函数时非常有用。