Name

Compute

Synopsis

Object obj = DataTable.Compute(String expression, String filter);

Returns the result of an aggregate expression for a subset of rows in the table meeting the filter criteria.

Parameters

obj

Returns an object containing the results computed.

expression

The expression to calculate.

filter

A filter that identifies a subset of rows for which the expression is computed.

Example

The following example demonstrates how to use the Compute( ) method to calculate the sum of a column for a subset of the rows filtered from the table:

DataTable dt = new DataTable();

dt.Columns.Add("OrderId", typeof(System.Int32));

dt.Columns.Add("OrderAmount", typeof(System.Decimal));



// ... add some rows



// computes the sum of order amounts for all orders with Id less than 10

Decimal totalOrderAmount= 

  (Decimal) dt.Compute("SUM(OrderAmount)", "OrderId<10");

Note

The expression must be set to an aggregate function. To compute a value based on an expression, create a DataColumn based on the expression and use that column in the expression.