IMapServer4.QueryDataStatistics Method

Calculates aggregate statistics for one or more fields on a table or layer.

[Visual Basic .NET]
Public Function QueryDataStatistics ( _
    ByVal MapName As String, _
    ByVal pTableDescription As IMapTableDescription, _
    ByVal pRequest As IStatisticsRequest, _
    ByVal pQueryFilter As IQueryFilter _
) As IRecordSet

[C#]
public IRecordSet QueryDataStatistics (
    string MapName,
    IMapTableDescription pTableDescription,
    IStatisticsRequest pRequest,
    IQueryFilter pQueryFilter
);

[C++]
HRESULT QueryDataStatistics(
  BSTR MapName,
  IMapTableDescription* pTableDescription,
  IStatisticsRequest* pRequest,
  IQueryFilter* pQueryFilter
);

[C++]
Parameters
MapName [in]

  MapName is a parameter of type BSTR
pTableDescription [in]

  pTableDescription is a parameter of type IMapTableDescription*
pRequest [in]

  pRequest is a parameter of type IStatisticsRequest*
pQueryFilter [in]

  pQueryFilter is a parameter of type IQueryFilter*

Product Availability

Remarks

QueryDataStatistics returns a recordset with requested statistics optionally grouped by or/and ordered by field(s) from a layer or a table. Use IStatisticsRequest to define what type of statistical information you would like to get back and how you want result be presented (e.g. sorted differently or result grouped by values from another field).

Please note that you must check IMapTableInfo2::SupportsStatistics before calling this function since not all layer type or source database supports this functionality.

This function honors defintion expression set to the layer or table. If you need to statistics from a set of features/rows that meet a criterion, then you can use IQueryFilter::WhereClause and pass this as a parameter to this function. When QueryFilter parameter is null, all features/rows are used (if defintion expression is not set) to compute statistics.

When IStatisticDescription::ResultFieldName is not specified, an auto-generated field name will be used.

Results:

If IStatisticRequest::GroupByFields is specified, statistics will be calculated separately for each unique attribute value. The output record will contain only one record if no GroupByFields is specified. If one is specified, there will be one record for each GroupByFields value.

Limitations:

• the function only works with numeric fields.

See Also