AggregateOperand.Avg(CriteriaOperator) Method

Creates a new AggregateOperand which returns the average of values calculated by the given aggregate expression. This expression is evaluated against elements of the AggregateOperand.CollectionProperty that match the specified AggregateOperand.Condition.

Namespace: DevExpress.Data.Filtering

Assembly: DevExpress.Data.v23.2.dll

NuGet Package: DevExpress.Data

Declaration

C#

public AggregateOperand Avg(
    CriteriaOperator aggregatedExpression
)

VB.NET

Public Function Avg(
    aggregatedExpression As CriteriaOperator
) As AggregateOperand

Parameters

Name	Type	Description
aggregatedExpression	CriteriaOperator	A CriteriaOperator object which specifies the aggregate expression.

Returns

Type	Description
AggregateOperand	An AggregateOperand object which calculates an aggregate expression.

Example

Example 1

Get average value of price property of all orders.

Expression:

LINQ

CriteriaOperator.FromLambda<Order, double>(x => FromLambdaFunctions.TopLevelAggregate<Order>().Average(c => c.Price));

Typed

new AggregateOperand(null, nameof(Order.Price), Aggregate.Avg);

String

CriteriaOperator.Parse("Avg(Price)");

Test

Input:

Name	Price
Item0	10
Item1	20

The result: 15

Example 2

Get list of orders with average order item price more than 100.

Expression:

LINQ

CriteriaOperator.FromLambda<Order>(x => x.OrderItems.Average(t => t.ItemPrice) > 100);

Typed

var aggrCriterion = new AggregateOperand(nameof(Order.OrderItems), nameof(OrderItem.ItemPrice) , Aggregate.Avg);
var resultCriterion = new BinaryOperator(aggrCriterion, 100, BinaryOperatorType.Greater);

String

CriteriaOperator.Parse("OrderItems.Avg(ItemPrice)>100");

Test

Input:

Order	OrderItem	OrderItemPrice
Order0
	Item0-0	10
	Item0-1	20
Order1
	Item1-0	100
	Item1-1	200
Order2
	Item2-0	30
	Item2-1	40
Order3
	Item3-0	300
	Item3-1	400

The result:

Order
Order1
Order3