This function calculates the statistics about a band set of a raster object.

Syntax

raster ST_SummaryStats(raster raster_obj)
raster ST_SummaryStats(raster raster_obj, cstring statsOption)
raster ST_SummaryStats(raster raster_obj,
                       cstring bands,
                       cstring statsOption)

Parameters

ParameterDescription
raster_objThe name of the raster object.
bandsThe sequence numbers of the bands. The value of this parameter can be an array of integers or an integer range. The integers start from 0. Examples: '0', '1-3', and '1,2,3'.
statsOptionsThe JSON string to specify the statistics that you want to calculate.

The following table describes the parameter that is contained in the value of the statsOptions parameter.

ParameterDescriptionTypeFormatDefault valueRemarks
approxSpecifies whether to use the sampling method to calculate statistics. booleanNonetrue
  • true: specifies to use the sampling method to calculate statistics. The statistics may be inaccurate.
  • false: specifies to calculate all statistics.

Examples

DO $$
declare
    rast raster;
begin
    select raster_obj into rast from raster_table where id = 1;
    rast = ST_SummaryStats(rast);
    update raster_table set raster_obj = rast where id = 1;
end;    
$$ LANGUAGE 'plpgsql';