/create/union

URL: http://GPUDB_IP_ADDRESS:GPUDB_PORT/create/union

Performs a union (concatenation) of one or more existing tables or views, the results of which are stored in a new view. It is equivalent to the SQL UNION ALL operator. Non-charN 'string' and 'bytes' column types cannot be included in a union, neither can columns with the property 'store_only'. Though not explicitly unions, intersect and except are also available from this endpoint.

Input Parameter Description

Name	Type	Description
table_name	string	Name of the table to be created. Has the same naming restrictions as tables.
table_names	array of strings	The list of table names making up the union. Must contain the names of one or more existing tables.
input_column_names	array of arrays of strings	The list of columns from each of the corresponding input tables.
output_column_names	array of strings	The list of names of the columns to be stored in the union.
options	map of strings	Optional parameters. Default value is an empty map ( {} ). Supported Parameters (keys) Parameter Description collection_name Name of a collection which is to contain the union. If the collection provided is non-existent, the collection will be automatically created. If empty, then the union will be a top-level table. Default value is ''. materialize_on_gpu If 'true' then the columns of the union will be cached on the GPU. Default value is 'false'. The allowed values are: true false mode If 'merge_views' then this operation will merge (i.e. union) the provided views. All 'table_names' must be views from the same underlying base table. Default value is 'union_all'. Supported Values Description 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). intersect Retains all unique rows that appear in both of the specified tables (only works on 2 tables). merge_views Merge two or more views (or views of views) of the same base data set into a new view. The resulting view would match the results of a SQL OR operation, e.g., if filter 1 creates a view using the expression 'x = 10' and filter 2 creates a view using the expression 'x <= 10', then the merge views operation creates a new view using the expression 'x = 10 OR x <= 10'. ttl Sets the TTL of the table specified in input parameter table_name. The value must be the desired TTL in minutes. persist If true then the union will be persisted as a regular table (it will not be automatically cleared unless a ttl is provided, and the table data can be modified in subsequent operations). If false then the union will be a read-only, memory-only temporary table. Default value is 'false'. The allowed values are: true false

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	'create_union_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 /create/union endpoint: Name Type Description table_name string Value of input parameter table_name. Empty string in case of an error.