Adding expression PostAggregator

[henris92]

Hello guys,

Last week I needed more complex postAggregation operations so I integrated post aggregation by expression.

It works like this. We have somekind of operation like so:

// We want this post aggregation operation to be calculated by Druid, 
$operation = "((CAST(\"sys_unique_event_count\", 'DOUBLE') / \"sys_event_count\") * 100)";

$queryBuilder->expression("example_dim", $operation);

"postAggregations": [
        {
            "type": "expression",
            "name": "example_dim",
            "expression": "((CAST(\"sys_unique_event_count\", 'DOUBLE') / \"sys_event_count\") * 100)"
        }
    ],

Thank you! I really like your druid php lib

[teyeheimans]

Hi @henris92,

Thanks for your Pull Request. We have decided not to merge it based on several reasons:

• Missing README / documentation
• Missing extra parameters like $ordering and $outputType
• Missing tests

However, we totally agree that this post aggregator was missing! We have created a new PR based on your changes, and added the missing parts. See https://github.com/level23/druid-client/pull/55

I want to thank you for your help. Feedback is always appreciated!

[henris92]

Thank you guys! I'll update my project and test it out :)