Add support for AggregationExpression in GroupOperation.sum [DATAMONGO-1784]

[spring-projects-issues]

Sergey Shcherbakov opened DATAMONGO-1784 and commented

After this ticket has been implemented, it is possible to use complex expressions in the aggregation request projections and group method parameters.
For example, there are min(), max(), first() aggregation methods that accept AggregationExpression in the GroupOperation class.
But there is no sum() aggregation method version that accepts AggregationExpression parameter.
Thus, it is not possible to express following MongoDB queries using Spring Data fluent API:

[
     { $match: { "myfield":"X" },
     { $group: {
           _id: { myfield: "$myfield"  },
           count: { $sum: 1 },
           lt5w: { $sum: { $cond:{ if: { $gte: [ "$myDate", new Date(ISODate().getTime() - 1000 * 60 * 60 * 24 * 7 * 5) ] }, then: 1, else: 0 } } },
           gt12w: { $sum: { $cond:{ if: { $gte: [ new Date(ISODate().getTime() - 1000 * 60 * 60 * 24 * 7 * 12), "$myDate"  ] }, then: 1, else: 0 } } }
         }
     }
])

---

Affects: 1.10.8 (Ingalls SR8), 2.0 GA (Kay)

Referenced from: pull request #501

Backported to: 1.10.8 (Ingalls SR8)

[spring-projects-issues]

Sergey Shcherbakov commented

Submitted a PR for this
#501
It would be great it could be ported to the Spring Framework 4.0 1.10.x branch as well

[spring-projects-issues]

Christoph Strobl commented

Thanks Sergey! Will have a look