Calculates unique combinations (groups) of values for the given columns in a given table or view and computes aggregates on each unique combination. This is somewhat analogous to an SQL-style SELECT...GROUP BY.
For aggregation details and examples, see Aggregation. For limitations, see Aggregation Limitations.
Any column(s) can be grouped on, and all column types except unrestricted-length strings may be used for computing applicable aggregates; columns marked as store-only are unable to be used in grouping or aggregation.
The results can be paged via the input parameter offset and input parameter limit parameters. For example, to get 10 groups with the largest counts the inputs would be: limit=10, options={"sort_order":"descending", "sort_by":"value"}.
Input parameter options can be used to customize behavior of this call e.g. filtering or sorting the results.
To group by columns 'x' and 'y' and compute the number of objects within each group, use: column_names=['x','y','count(*)'].
To also compute the sum of 'z' over each group, use: column_names=['x','y','count(*)','sum(z)'].
Available aggregation functions are: count(*), sum, min, max, avg, mean, stddev, stddev_pop, stddev_samp, var, var_pop, var_samp, arg_min, arg_max and count_distinct.
Available grouping functions are Rollup, Cube, and Grouping Sets
This service also provides support for Pivot operations.
Filtering on aggregates is supported via expressions using aggregation functions supplied to having.
The response is returned as a dynamic schema. For details see: dynamic schemas documentation.
If a result_table name is specified in the input parameter options, the results are stored in a new table with that name--no results are returned in the response. Both the table name and resulting column names must adhere to standard naming conventions; column/aggregation expressions will need to be aliased. If the source table's shard key is used as the grouping column(s) and all result records are selected (input parameter offset is 0 and input parameter limit is -9999), the result table will be sharded, in all other cases it will be replicated. Sorting will properly function only if the result table is replicated or if there is only one processing node and should not be relied upon in other cases. Not available when any of the values of input parameter column_names is an unrestricted-length string.
Input Parameter Description
Name | Type | Description | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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table_name | string | Name of an existing table or view on which the operation will be performed, in [schema_name.]table_name format, using standard name resolution rules. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
column_names | array of strings | List of one or more column names, expressions, and aggregate expressions. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
offset | long | A positive integer indicating the number of initial results to skip (this can be useful for paging through the results). The default value is 0.The minimum allowed value is 0. The maximum allowed value is MAX_INT. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
limit | long | A positive integer indicating the maximum number of results to be returned, or END_OF_SET (-9999) to indicate that the maximum number of results allowed by the server should be returned. The number of records returned will never exceed the server's own limit, defined by the max_get_records_size parameter in the server configuration. Use output parameter has_more_records to see if more records exist in the result to be fetched, and input parameter offset & input parameter limit to request subsequent pages of results. The default value is -9999. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
encoding | string | Specifies the encoding for returned records. The default value is binary.
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options | map of string to strings | Optional parameters. The default value is an empty map ( {} ).
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Output Parameter Description
Name | Type | Description | ||||
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response_schema_str | string | Avro schema of output parameter binary_encoded_response or output parameter json_encoded_response. | ||||
binary_encoded_response | bytes | Avro binary encoded response. | ||||
json_encoded_response | string | Avro JSON encoded response. | ||||
total_number_of_records | long | Total/Filtered number of records. | ||||
has_more_records | boolean | Too many records. Returned a partial set. | ||||
info | map of string to strings | Additional information. The default value is an empty map ( {} ).
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