org.apache.spark.sql.Row为Int [英] org.apache.spark.sql.Row to Int

问题描述

我试图让从火花SQL SQL语句的整数。

I'm trying to get an Integer from a SQL statement in spark-sql.

var num_en = ctx.sql("SELECT count(*) FROM table WHERE lang = 'en'")
num = num_en.collect()(0)

num_en是SchemaRDD，和num，根据错误，我得到一个行。

num_en is a SchemaRDD, and num, according to the error I get, a "Row".

<console>:144: error: type mismatch;
 found   : org.apache.spark.sql.Row
    (which expands to)  org.apache.spark.sql.catalyst.expressions.Row

问题是，我无法找到任何有用的文档，无论是org.apache.spark.sql.Row或org.apache.spark.sql.catalyst.ex pressions.Row。

The problem is that I can't find any useful documentation for either org.apache.spark.sql.Row or org.apache.spark.sql.catalyst.expressions.Row.

我怎么能提取这一整数值，以备后用SQL语句返回？

How can I extract this one integer value that the SQL statement returns for later use?

推荐答案

最好的文档是源

<一个href=\"https://github.com/apache/spark/blob/master/sql/core/src/main/scala/org/apache/spark/sql/api/java/Row.scala#L37\"相对=nofollow> Row.scala

  /**
   * Returns the value of column `i` as an int.  This function will throw an exception if the value
   * is at `i` is not an integer, or if it is null.
   */
  def getInt(i: Int): Int =
    row.getInt(i)

适用于你的例子：

Applied to your example:

num = num_en.collect()(0).getInt(0)

这篇关于org.apache.spark.sql.Row为Int的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！