Returns all the unique values from a particular column (specified by input parameter column_name) of a particular table or view (specified by input parameter table_name). If input parameter column_name is a numeric column, the values will be in output parameter binary_encoded_response. Otherwise if input parameter column_name is a string column, the values will be in output parameter json_encoded_response. The results can be paged via input parameter offset and input parameter limit parameters.
Columns marked as store-only are unable to be used with this function.
To get the first 10 unique values sorted in descending order input parameter options would be:
{"limit":"10","sort_order":"descending"}
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 name must adhere to standard naming conventions; any column expression will need to be aliased. If the source table's shard key is used as the input parameter column_name, 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 if the value of input parameter column_name is an unrestricted-length string.
Input Parameter Description
| Name | Type | Description | ||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 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_name | string | Name of the column or an expression containing one or more column names on which the unique function would be applied. | ||||||||||||||||||||||||||||||
| 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 | ||||
|---|---|---|---|---|---|---|
| table_name | string | The same table name as was passed in the parameter list. | ||||
| 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. | ||||
| 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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