CREATE EXTERNAL TABLE

Warning

The CREATE EXTERNAL TABLE syntax is deprecated, and will be removed in future versions.

Starting with SQream DB v2020.2, external tables have been renamed to foreign tables, and use a more flexible foreign data wrapper concept. See CREATE FOREIGN TABLE instead.

Upgrading to a new version of SQream DB converts existing tables automatically. When creating a new external tables, use the new foreign table syntax.

CREATE TABLE creates a new external table in an existing database.

See more in the External tables guide.

Tip

  • Data in an external table can change if the sources change, and frequent access to remote files may harm performance.
  • To create a regular table, see CREATE TABLE

Permissions

The role must have the CREATE permission at the database level.

Syntax

create_table_statement ::=
    CREATE [ OR REPLACE ] EXTERNAL TABLE [schema_name].table_name (
        { column_def [, ...] }
    )
    USING FORMAT format_def
    WITH { external_table_option [ ...] }
    ;

schema_name ::= identifier

table_name ::= identifier

format_def ::= { PARQUET | ORC | CSV }

external_table_option ::= {
   PATH '{ path_spec }'
   | FIELD DELIMITER '{ field_delimiter }'
   | RECORD DELIMITER '{ record_delimiter }'
   | AWS_ID '{ AWS ID }'
   | AWS_SECRET '{ AWS SECRET }'
}

path_spec ::= { local filepath | S3 URI | HDFS URI }

field_delimiter ::= delimiter_character

record_delimiter ::= delimiter_character

column_def ::= { column_name type_name [ default ] [ column_constraint ] }

column_name ::= identifier

column_constraint ::=
    { NOT NULL | NULL }

default ::=

    DEFAULT default_value
    | IDENTITY [ ( start_with [ , increment_by ] ) ]

Parameters

Parameter Description
OR REPLACE Create a new table, and overwrite any existing table by the same name. Does not return an error if the table already exists. CREATE OR REPLACE does not check the table contents or structure, only the table name.
schema_name The name of the schema in which to create the table.
table_name The name of the table to create, which must be unique inside the schema.
column_def A comma separated list of column definitions. A minimal column definition includes a name identifier and a datatype. Other column constraints and default values can be added optionally.
USING FORMAT ... Specifies the format of the source files, such as PARQUET, ORC, or CSV.
WITH PATH ... Specifies a path or URI of the source files, such as /path/to/*.parquet.
FIELD DELIMITER Specifies the field delimiter for CSV files. Defaults to ,.
RECORD DELIMITER Specifies the record delimiter for CSV files. Defaults to a newline, \n
AWS_ID, AWS_SECRET Credentials for authenticated S3 access

Examples

A simple table from Tab-delimited file (TSV)

CREATE OR REPLACE EXTERNAL TABLE cool_animals
  (id INT NOT NULL, name VARCHAR(30) NOT NULL, weight FLOAT NOT NULL)
USING FORMAT csv
WITH  PATH  '/home/rhendricks/cool_animals.csv'
      FIELD DELIMITER '\t';

A table from a directory of Parquet files on HDFS

CREATE EXTERNAL TABLE users
  (id INT NOT NULL, name VARCHAR(30) NOT NULL, email VARCHAR(50) NOT NULL)
USING FORMAT Parquet
WITH  PATH  'hdfs://hadoop-nn.piedpiper.com/rhendricks/users/*.parquet';

A table from a bucket of files on S3

CREATE EXTERNAL TABLE users
  (id INT NOT NULL, name VARCHAR(30) NOT NULL, email VARCHAR(50) NOT NULL)
USING FORMAT Parquet
WITH  PATH  's3://pp-secret-bucket/users/*.parquet'
      AWS_ID 'our_aws_id'
      AWS_SECRET 'our_aws_secret';

Changing an external table to a regular table

Materializes an external table into a regular table.

CREATE TABLE real_table
 AS SELECT * FROM external_table;