-
Type:
Bug
-
Status: Closed
-
Priority:
Major
-
Resolution: Fixed
-
Affects Version/s: V4.0_CS02
-
Fix Version/s: V4.0_CSD04
-
Component/s: Data Aggregation
-
Labels:None
-
Environment:
Applied
-
Proposal:
-
Resolution:
Section 3.1 introduces $count as one of several options for aggregate expressions.
Example 57 applies $count relative to a collection-valued navigation property, which is a different use case that is backed by the commonExpr ABNF rule to address the count of a collection (see URL spec, section 4.8). Since section 3.1 requires commonExpr to be augmented with an aggregation method, such a method must be added to the request in the example.
The current aggregation ABNF contains a rule for $count with a path prefix, which needs to be cleaned up accordingly.
Further discussion 2020-5-28:
The previous syntax was, in fact, valid, since $count is an aggregate expression, just as Amount with Sum is an aggregate expression.
2018-12-06
re-opened while reviewing the proposed application 2018-12-6.
Concern that use of unprefixed $count within a navigation expression inside an aggregation as implicitly referencing the navigation set, as per the following example, is unexpected and inconsistent.
$apply=groupby((Name),aggregate(Sales($count as SalesCount),Sales(Amount with sum as Total)))
The semantics of the expression within the parens following the navigation is that it operates on each instance within the navigation set, so $count having a special meaning here would be inconsistent.
At the top level, this can be a shortcut for "1 with sum", as in:
Sales?$apply=groupby((Product/Name),aggregate($count as SalesCount,Amount with sum as Total))
with the key difference that, for an empty input set, 1 with sum would be null, while $count would be zero.
Resolved as proposed 2018-11-15.
Resolved as proposed 2020-5-28.