如何在Apache Spark中执行SQL查询

问题描述

我对 Apache Spark 非常陌生.
我已经在本地Windows机器上配置了spark 2.0.2.我已经完成了带有火花的字数统计"示例.
现在，我在执行SQL查询时遇到了问题.我已经搜索了相同的内容，但没有得到正确的指导.

I am very new to Apache Spark.
I have already configured spark 2.0.2 on my local windows machine.I have done with "word count" example with spark.
Now, I have the problem in executing the SQL Queries.I have searched for the same , but not getting proper guidance .

任何帮助，不胜感激！
感谢进阶！！

Any help greatly appreciated!
Thanks in Advanced!!

推荐答案

所以您需要执行以下操作才能完成它，

So you need to do these things to get it done ,

在Spark 2.0.2中，我们有SparkSession，其中包含SparkContext实例和sqlContext实例.

In Spark 2.0.2 we have SparkSession which contains SparkContext instance as well as sqlContext instance.

因此步骤将是:

步骤1:创建SparkSession

Step 1: Create SparkSession

val spark = SparkSession.builder().appName("MyApp").master("local[*]").getOrCreate()

第2步:在您的情况下，从数据库中加载Mysql.

Step 2: Load from the database in your case Mysql.

val loadedData=spark
      .read
      .format("jdbc")
      .option("url", "jdbc:mysql://localhost:3306/mydatabase")
      .option("driver", "com.mysql.jdbc.Driver")
      .option("mytable", "mydatabase")
      .option("user", "root")
      .option("password", "toor")
      .load().createOrReplaceTempView("mytable")

步骤3:现在，您可以像在SqlDatabase中一样运行SqlQuery.

Step 3: Now you can run your SqlQuery just like you do in SqlDatabase.

val dataFrame=spark.sql("Select * from mytable")
dataFrame.show()

P.S:如果您使用DataFrame Api更好，或者如果使用DataSet Api更好，但是对于那些您需要阅读文档.

P.S: It would be better if you use DataFrame Api's or even better if DataSet Api's , but for those you need to go through the documentation.

链接到文档: https://spark.apache.org/docs/2.0.0/api/scala/index.html#org.apache.spark.sql.Dataset

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