我定义了两个表是这样的:Left反加入Spark?
val tableName = "table1"
val tableName2 = "table2"
val format = new SimpleDateFormat("yyyy-MM-dd")
val data = List(
List("mike", 26, true),
List("susan", 26, false),
List("john", 33, true)
)
val data2 = List(
List("mike", "grade1", 45, "baseball", new java.sql.Date(format.parse("1957-12-10").getTime)),
List("john", "grade2", 33, "soccer", new java.sql.Date(format.parse("1978-06-07").getTime)),
List("john", "grade2", 32, "golf", new java.sql.Date(format.parse("1978-06-07").getTime)),
List("mike", "grade2", 26, "basketball", new java.sql.Date(format.parse("1978-06-07").getTime)),
List("lena", "grade2", 23, "baseball", new java.sql.Date(format.parse("1978-06-07").getTime))
)
val rdd = sparkContext.parallelize(data).map(Row.fromSeq(_))
val rdd2 = sparkContext.parallelize(data2).map(Row.fromSeq(_))
val schema = StructType(Array(
StructField("name", StringType, true),
StructField("age", IntegerType, true),
StructField("isBoy", BooleanType, false)
))
val schema2 = StructType(Array(
StructField("name", StringType, true),
StructField("grade", StringType, true),
StructField("howold", IntegerType, true),
StructField("hobby", StringType, true),
StructField("birthday", DateType, false)
))
val df = sqlContext.createDataFrame(rdd, schema)
val df2 = sqlContext.createDataFrame(rdd2, schema2)
df.createOrReplaceTempView(tableName)
df2.createOrReplaceTempView(tableName2)
我试图建立查询到从没有匹配的行表2表1返回行。 我尝试使用此查询做到这一点:
Select * from table1 LEFT JOIN table2 ON table1.name = table2.name AND table1.age = table2.howold AND table2.name IS NULL AND table2.howold IS NULL
但这只是给了我从表1中的所有行:
列表({“名”:“约翰”,“年龄”: 33,isBoy:true}, {“name”:“susan”,“age”:26,“isBoy”:false}, {“name”:“mike”,“age”:26,“isBoy “:true})
如何在Spark中有效地进行这种连接?
我正在查找SQL查询,因为我需要能够指定要在两个表之间进行比较的列,而不仅仅是比较像其他推荐问题那样逐行比较。像使用减法,除了等。
的可能的复制[火花:减去两个DataFrames](http://stackoverflow.com/questions/29537564/spark-subtract-two-dataframes) –
根据您的编辑和评论我的答案,我认为你正在寻找: http://stackoverflow.com/questions/29537564/spark-subtract-two-dataframes值得注意的是@Interfector对第一个回答的评论 –