hpcc-systems/HPCC-Platform — pull request #690 by ghalliday (2011-10-14 16:03:12+00:00)
Title: Fix problems with AGGREGATE on complex datasets

There were several problems:
* MAX(IF(cond,NULL,ds), some-field) could generate an unknown dataset
* The wrong selector was used when builing a temporary set
* Assignments to child query results were lost from the transforms
* The generated code could incorrectly release a child row some some
(unusual) situations.

Signed-off-by: Gavin Halliday