累积总和

Created: November-22, 2018

根据雇主的角色计算雇主的工资移动平均值：

val cumSum = sampleData.withColumn("cumulativeSum", sum(sampleData("Salary"))
             .over( Window.partitionBy("Role").orderBy("Salary")))

orderBy() 对工资列进行排序并计算累积金额。

scala> cumSum.show
+------+---------+------+-------------+                                         
|  Name|     Role|Salary|cumulativeSum|
+------+---------+------+-------------+
| simon|Developer| 98000|        98000|
|  mark|Developer|108000|       206000|
| henry|Developer|110000|       316000|
|   bob|Developer|125000|       441000|
|  eric|Developer|144000|       585000|
| peter|Developer|185000|       770000|
|   jon|   Tester| 65000|        65000|
|  carl|   Tester| 70000|       135000|
|carlos|   Tester| 75000|       210000|
| roman|   Tester| 82000|       292000|
+------+---------+------+-------------+