IT:AD:Breeze.JS:HowTo:Develop Queries/Aggregates
Summary
At present (Q1/2014), Breeze can't process Agregate commands.
Breeze does not yet support aggregate queries (count, sum, average, etc.). But we can get the count of a query without retrieving any actual data using the "take(0), inlineCount()" trick.
Process
But there workarounds:
var inlineCount, resultCount, query;
query = EntityQuery.from("Products")
.where("ProductName", "startsWith", "C");
.take(0).inlineCount();
em.executeQuery(query).then(function(data) {
resultsCount = data.results.length; // 0
inlineCount = data.inlineCount; // count of products beginning with 'C'
});