apache/spark — pull request #1151 by YanjieGao (2014-06-20 07:57:52+00:00)
Title: Spark SQL basicOperators  add Ecept operator

Hi all,
I want to submit a Except operator in basicOperators.scala
In SQL case.SQL support two table do except operator.
select * from table1
except
select * from table2
This operator support the substract function .Return an table with the elements from `this` that are not in `other`.