URL: http://GPUDB_IP_ADDRESS:GPUDB_PORT/aggregate/statistics
Calculates the requested statistics of the given column(s) in a given table.
 The available statistics are:
 count (number of total objects), mean, stdv (standard deviation), variance, skew, kurtosis, sum, min, max, weighted_average, cardinality (unique count), estimated_cardinality, percentile, and percentile_rank.
Estimated cardinality is calculated by using the hyperloglog approximation technique.
Percentiles and percentile ranks are approximate and are calculated using the tdigest algorithm. They must include the desired percentile/percentile_rank. To compute multiple percentiles each value must be specified separately (i.e. 'percentile(75.0),percentile(99.0),percentile_rank(1234.56),percentile_rank(5)').
A second, commaseparated value can be added to the percentile statistic to calculate percentile resolution, e.g., a 50th percentile with 200 resolution would be 'percentile(50,200)'.
The weighted average statistic requires a weight column to be specified in weight_column_name. The weighted average is then defined as the sum of the products of input parameter column_name times the weight_column_name values divided by the sum of the weight_column_name values.
Additional columns can be used in the calculation of statistics via additional_column_names. Values in these columns will be included in the overall aggregate calculationindividual aggregates will not be calculated per additional column. For instance, requesting the count & mean of input parameter column_name x and additional_column_names y & z, where x holds the numbers 110, y holds 1120, and z holds 2130, would return the total number of x, y, & z values (30), and the single average value across all x, y, & z values (15.5).
The response includes a list of key/value pairs of each statistic requested and its corresponding value.
Input Parameter Description
Name  Type  Description  

table_name  string  Name of the table on which the statistics operation will be performed, in [schema_name.]table_name format, using standard name resolution rules.  
column_name  string  Name of the primary column for which the statistics are to be calculated.  
stats  string  Comma separated list of the statistics to calculate, e.g. "sum,mean".
 
options  map of string to strings  Optional parameters. The default value is an empty map ( {} ).

Output Parameter Description
The GPUdb server embeds the endpoint response inside a standard response structure which contains status information and the actual response to the query. Here is a description of the various fields of the wrapper:
Name  Type  Description  

status  String  'OK' or 'ERROR'  
message  String  Empty if success or an error message  
data_type  String  'aggregate_statistics_request' or 'none' in case of an error  
data  String  Empty string  
data_str  JSON or String  This embedded JSON represents the result of the /aggregate/statistics endpoint:
Empty string in case of an error. 