或连接结果的条件在交叉上加入

Question

我正在尝试在Spark上加入两个数据集，我使用Spark版本2.1，

SELECT * 
  FROM Tb1 
       INNER JOIN Tb2 
          ON Tb1.key1=Tb2.key1 
            OR Tb1.key2=Tb2.Key2

但它会导致交叉加入，我该如何加入两个表并仅获得匹配的记录？

我也尝试了外部加入，但它也迫使我更改以交叉加入？

Answer 1

尝试此方法

from pyspark.sql import SQLContext as SQC
sqc = SQC(sc)
x = [(1,2,3), (4,5,6), (7,8,9), (10,11,12), (13,14,15)]
y = [(1,4,5), (4,5,6), (10,11,16),(34,23,31), (56,14,89)]
x_df = sqc.createDataFrame(x,["x","y","z"])
y_df = sqc.createDataFrame(y,["x","y","z"])
cond = [(x_df.x == y_df.x) | ( x_df.y == y_df.y)]
x_df.join(y_df,cond, "inner").show()

输出

+---+---+---+---+---+---+
|  x|  y|  z|  x|  y|  z|
+---+---+---+---+---+---+
|  1|  2|  3|  1|  4|  5|
|  4|  5|  6|  4|  5|  6|
| 10| 11| 12| 10| 11| 16|
| 13| 14| 15| 56| 14| 89|
+---+---+---+---+---+---+

Answer 2

通过加入两次：

 select * 
   from Tb1 
      inner join Tb2 
         on Tb1.key1=Tb2.key1 
      inner join Tb2 as Tb22 
         on Tb1.key2=Tb22.Key2  

或左加入两者：

 select * 
   from Tb1 
      left join Tb2 
         on Tb1.key1=Tb2.key1 
      left join Tb2 as Tb22 
         on Tb1.key2=Tb22.Key2