madlib/madlib — pull request #214 by aojwang (2012-08-23 09:25:34+00:00)
Title: score function return 'divide by zero' on madelon, since the class column is malformat.

JIRA: MADLIB-632.
We use left join to ensure all the rows of classification/scoring table were breakup. And the class labels which don't appear in the training dataset will be treat as 0 (encoded value). Therefore, during scoring, those samples with 0 class label will be regarded misclassified.