create_union

Name of the table to be created, in [schema_name.]table_name format, using standard name resolution rules and meeting table naming criteria.

The list of table names to merge, in [schema_name.]table_name format, using standard name resolution rules. Must contain the names of one or more existing tables. The user can provide a single element (which will be automatically promoted to a list internally) or a list.

The list of columns from each of the corresponding input tables. The user can provide a single element (which will be automatically promoted to a list internally) or a list.

The list of names of the columns to be stored in the output table. The user can provide a single element (which will be automatically promoted to a list internally) or a list.

Optional parameters. Allowed keys are:

• create_temp_table – If true, a unique temporary table name will be generated in the sys_temp schema and used in place of input parameter table_name. If persist is false (or unspecified), then this is always allowed even if the caller does not have permission to create tables. The generated name is returned in qualified_table_name. Allowed values are:

  • true

  • false

  The default value is ‘false’.

• collection_name – [DEPRECATED–please specify the containing schema for the projection as part of input parameter table_name and use GPUdb.create_schema() to create the schema if non-existent] Name of the schema for the output table. If the schema provided is non-existent, it will be automatically created. The default value is ‘’.

• mode – The mode describes what rows of the tables being unioned will be retained. Allowed values are:

  • union_all – Retains all rows from the specified tables.

  • union – Retains all unique rows from the specified tables (synonym for union_distinct).

  • union_distinct – Retains all unique rows from the specified tables.

  • except – Retains all unique rows from the first table that do not appear in the second table (only works on 2 tables).

  • except_all – Retains all rows(including duplicates) from the first table that do not appear in the second table (only works on 2 tables).

  • intersect – Retains all unique rows that appear in both of the specified tables (only works on 2 tables).

  • intersect_all – Retains all rows(including duplicates) that appear in both of the specified tables (only works on 2 tables).

  The default value is ‘union_all’.

• chunk_size – Indicates the number of records per chunk to be used for this output table.

• chunk_column_max_memory – Indicates the target maximum data size for each column in a chunk to be used for this output table.

• chunk_max_memory – Indicates the target maximum data size for all columns in a chunk to be used for this output table.

• create_indexes – Comma-separated list of columns on which to create indexes on the output table. The columns specified must be present in input parameter output_column_names.

• partition_type – Partitioning scheme to use for the output table. Allowed values are:

  • RANGE – Use range partitioning.

  • INTERVAL – Use interval partitioning.

  • LIST – Use list partitioning.

  • HASH – Use hash partitioning.

  • SERIES – Use series partitioning.

• partition_keys – Comma-separated list of partition keys, which are the columns or column expressions by which records will be assigned to partitions defined by partition_definitions.

• partition_definitions – Comma-separated list of partition definitions, whose format depends on the choice of partition_type. See range partitioning, interval partitioning, list partitioning, hash partitioning, or series partitioning for example formats.

• is_automatic_partition – If true, a new partition will be created for values which don’t fall into an existing partition. Currently only supported for list partitions. Allowed values are:

  • true

  • false

  The default value is ‘false’.

• ttl – Sets the TTL of the output table specified in input parameter table_name.

• persist – If true, then the output table specified in input parameter table_name will be persisted and will not expire unless a ttl is specified. If false, then the output table will be an in-memory table and will expire unless a ttl is specified otherwise. Allowed values are:

  • true

  • false

  The default value is ‘false’.

• view_id – ID of view of which this output table is a member. The default value is ‘’.

• force_replicated – If true, then the output table specified in input parameter table_name will be replicated even if the source tables are not. Allowed values are:

  • true

  • false

  The default value is ‘false’.

• strategy_definition – The tier strategy for the table and its columns.

• compression_codec – The default compression codec for this table’s columns.

• no_count – Return a count of 0 for the union table response to avoid the cost of counting; optimization needed for many chunk virtual unions. The default value is ‘false’.

The default value is an empty dict ( ).

Value of input parameter table_name.

Additional information. Allowed keys are:

• count – Number of records in the final table.

• qualified_table_name – The fully qualified name of the result table (i.e. including the schema).

The default value is an empty dict ( ).