[IGNITE-4543] .NET: Support multiple aggregates in LINQ

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: platforms
• Labels: .NET linq
• Assignee: Unassigned
• Reporter: Pavel Tupitsyn
• Created: 12/Jan/17 14:52
• Updated: 04/Jul/17 15:57

Description

Provide a way to express multiple aggregates in LINQ like we do in SQL:
SELECT MIN(salary), MAX(salary) from Employee,

LINQ to SQL and EntityFramework allow constructs like these:

        [Test]
        public void TestAggregatesMultiple()
        {
            var ints = GetPersonCache().AsCacheQueryable().Select(x => x.Key);

            var res = ints.GroupBy(x => 1).Select(g => new {Sum = g.Sum(), Avg = g.Average()}).Single();

            Assert.AreEqual(ints.Sum(), res.Sum);
            Assert.AreEqual(ints.Average(), res.Avg);

            var res2 = ints.Select(x => new {Sum = ints.Sum(), Avg = ints.Average()}).First();
            
            Assert.AreEqual(ints.Sum(), res2.Sum);
            Assert.AreEqual(ints.Average(), res2.Avg);
        }