Mysql 如何使用spark sql区分两个表?
现在我需要使用spark sql区分两个表,我发现sql server的答案如下:Mysql 如何使用spark sql区分两个表?,mysql,sql-server,apache-spark-sql,Mysql,Sql Server,Apache Spark Sql,现在我需要使用spark sql区分两个表,我发现sql server的答案如下: (SELECT * FROM table1 EXCEPT SELECT * FROM table2) UNION ALL (SELECT * FROM table2 EXCEPT SELECT * FROM table1) 希望有人能告诉我如何在SQLServer中这样使用spark sql?(不在乎特殊颜色,只需使用*)您可以这样做: scala> val df1=sc
(SELECT *
FROM table1
EXCEPT
SELECT *
FROM table2)
UNION ALL
(SELECT *
FROM table2
EXCEPT
SELECT *
FROM table1)
希望有人能告诉我如何在SQLServer中这样使用spark sql?(不在乎特殊颜色,只需使用*)您可以这样做:
scala> val df1=sc.parallelize(Seq((1,2),(3,4))).toDF("a","b")
df1: org.apache.spark.sql.DataFrame = [a: int, b: int]
scala> val df2=sc.parallelize(Seq((1,2),(5,6))).toDF("a","b")
df2: org.apache.spark.sql.DataFrame = [a: int, b: int]
scala> df1.create
createOrReplaceTempView createTempView
scala> df1.createTempView("table1")
scala> df2.createTempView("table2")
scala> spark.sql("select * from table1 EXCEPT select * from table2").show
+---+---+
| a| b|
+---+---+
| 3| 4|
+---+---+
scala> spark.sql("(select * from table2 EXCEPT select * from table1) UNION ALL (select * from table1 EXCEPT select * from table2)").show
+---+---+
| a| b|
+---+---+
| 5| 6|
| 3| 4|
+---+---+
注意:在您的情况下,您必须从JDBC调用中生成数据帧,然后注册表并执行操作。您可以这样做:
scala> val df1=sc.parallelize(Seq((1,2),(3,4))).toDF("a","b")
df1: org.apache.spark.sql.DataFrame = [a: int, b: int]
scala> val df2=sc.parallelize(Seq((1,2),(5,6))).toDF("a","b")
df2: org.apache.spark.sql.DataFrame = [a: int, b: int]
scala> df1.create
createOrReplaceTempView createTempView
scala> df1.createTempView("table1")
scala> df2.createTempView("table2")
scala> spark.sql("select * from table1 EXCEPT select * from table2").show
+---+---+
| a| b|
+---+---+
| 3| 4|
+---+---+
scala> spark.sql("(select * from table2 EXCEPT select * from table1) UNION ALL (select * from table1 EXCEPT select * from table2)").show
+---+---+
| a| b|
+---+---+
| 5| 6|
| 3| 4|
+---+---+
注意:在您的情况下,您必须从JDBC调用中生成数据帧,然后注册表并执行操作。对特定主键的连接不是更有效吗?使用Except将表a中的每一行与表B中的每一行进行比较是否正确?特定主键上的联接不是更有效吗?使用Except将表A中的每一行与表B中的每一行进行比较,对吗?