我试图返回数据框的列表或元组并显示它们,但是我无法显示它,所以有人可以帮忙
我尝试返回list(dataframes),然后在主目录中调用.show 方法
def dbReader():List[DataFrame]= {
val abcd_df_user = spark.read
.format("jdbc")
.option("url", "jdbc:postgresql://localhost/abcd?user=postgres&password=postgres")
.option("dbtable", "User_Testing")
.option("user", "postgres")
.option("password", "postgres")
.option("driver", "org.postgresql.Driver")
.load()
.createOrReplaceTempView("abcd_user_testing")
val user_Testing = spark.sql("""select * from abcd_user_testing""")
//.createOrReplaceTempView("All_User__Data")
val abcd_df_employee = spark.read
.format("jdbc")
.option("url", "jdbc:postgresql://localhost/abcd?user=postgres&password=postgres")
.option("dbtable", "employee")
.option("user", "postgres")
.option("password", "postgres")
.option("driver", "org.postgresql.Driver")
.load()
.createOrReplaceTempView("Employee_Table")
val employee_df = spark.sql("""select emp_id,emp_name from Employee_Table""")
List(employee_df,user_Testing)
}
主要方法:
object readinfromdbusingdf extends App {
val readingfromdbusingdf=new readingfromdbusingdf()
readingfromdbusingdf.dbReader().show(10)
预期结果:应该在控制台上同时显示两个数据框