// 创建视图
data.createOrReplaceTempView("Affairs")
val df1 = spark.sql("SELECT * FROM Affairs WHERE age BETWEEN 20 AND 25")
df1: org.apache.spark.sql.DataFrame = [affairs: double, gender: string ... 7 more fields]
// 子查询
val df2 = spark.sql("select gender, age,rating from ( SELECT * FROM Affairs WHERE age BETWEEN 20 AND 25 ) t ")
df2: org.apache.spark.sql.DataFrame = [gender: string, age: double ... 1 more field]
df2.show
+------+----+------+
|gender| age|rating|
+------+----+------+
| male|22.0| 3.0|
|female|22.0| 3.0|
| male|22.0| 5.0|
+------+----+------+
