apache-spark - Spark 中的 sort 和 orderBy 函数有什么区别

Question

sort 和 orderBy spark DataFrame 有什么区别？

scala> zips.printSchema
root
 |-- _id: string (nullable = true)
 |-- city: string (nullable = true)
 |-- loc: array (nullable = true)
 |    |-- element: double (containsNull = true)
 |-- pop: long (nullable = true)
 |-- state: string (nullable = true)

下面的命令产生相同的结果:

zips.sort(desc("pop")).show
zips.orderBy(desc("pop")).show

Answer 1

OrderBy 只是 sort 函数的别名。

从 Spark 文档:

  /**
   * Returns a new Dataset sorted by the given expressions.
   * This is an alias of the `sort` function.
   *
   * @group typedrel
   * @since 2.0.0
   */
  @scala.annotation.varargs
  def orderBy(sortCol: String, sortCols: String*): Dataset[T] = sort(sortCol, sortCols : _*)