GitHub user wzhfy opened a pull request: https://github.com/apache/spark/pull/15443
[SPARK-17881] [SQL] Aggregation function for generating string histograms ## What changes were proposed in this pull request? This agg function generates equi-width histograms in the form of Map(value: String, frequency: Long) for string type columns, with a maximum number of histogram bins. It returns a empty result if the ndv(number of distinct value) of the column exceeds the maximum number allowed. ## How was this patch tested? add test cases You can merge this pull request into a Git repository by running: $ git pull https://github.com/wzhfy/spark stringHistogram Alternatively you can review and apply these changes as the patch at: https://github.com/apache/spark/pull/15443.patch To close this pull request, make a commit to your master/trunk branch with (at least) the following in the commit message: This closes #15443 ---- commit a843920983914de7efd21608b8f0e39c70b210d7 Author: wangzhenhua <wangzhen...@huawei.com> Date: 2016-10-12T01:02:37Z add agg function to generate string histogram ---- --- If your project is set up for it, you can reply to this email and have your reply appear on GitHub as well. If your project does not have this feature enabled and wishes so, or if the feature is enabled but not working, please contact infrastructure at infrastruct...@apache.org or file a JIRA ticket with INFRA. --- --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org