RavenDB aggregation query

RavenDB is a document oriented key value storage database with powerful aggregation query capabilities built-in. Here are some common aggregation queries and corresponding examples supported by RavenDB: 1. Count: -Query the quantity of all documents: csharp var count = session.Query<YourEntity>().Count(); -Condition counting, such as counting the number of documents that meet a certain condition: csharp var count = session.Query<YourEntity>() .Where(x => x.Property == SomeValue) .Count(); 2. Sum: -Calculate the sum of a certain attribute in all documents: csharp var sum = session.Query<YourEntity>().Sum(x => x.Property); -Conditional summation, such as calculating the sum of document attributes that meet a certain condition: csharp var sum = session.Query<YourEntity>() .Where(x => x.Property > SomeValue) .Sum(x => x.Property); 3. Average: -Calculate the average value of a certain attribute: csharp var average = session.Query<YourEntity>().Average(x => x.Property); 4. Max and Min: -Calculate the maximum and minimum values of a certain attribute: csharp var max = session.Query<YourEntity>().Max(x => x.Property); var min = session.Query<YourEntity>().Min(x => x.Property); 5. GroupBy: -Group based on a certain attribute and calculate the number of each group: csharp var groups = session.Query<YourEntity>() .GroupBy(x => x.Property) .Select(g => new { Property = g.Key, Count = g.Count() }) .ToList(); 6. Distinct: -Obtain all unique values for a property: csharp var distinctValues = session.Query<YourEntity>() .Select(x => x.Property) .Distinct() .ToList(); It should be noted that the 'YourEntity' in the above example represents a specific entity class or document type, and you need to replace it with your own actual type. In addition, it is also necessary to ensure that you have established the corresponding RavenDB document storage and added appropriate document data.