SnowConvert AI - BigQuery - CREATE TABLE¶

Grammar syntax¶

CREATE [ OR REPLACE ] [ TEMP | TEMPORARY ] TABLE [ IF NOT EXISTS ]
table_name
[(
  column | constraint_definition[, ...]
)]
[DEFAULT COLLATE collate_specification]
[PARTITION BY partition_expression]
[CLUSTER BY clustering_column_list]
[OPTIONS(table_option_list)]
[AS query_statement]

Sample Source Patterns¶

DEFAULT COLLATE¶

BigQuery¶

CREATE TABLE table1 (
    col1 STRING 
) 
DEFAULT COLLATE 'und:ci';

Snowflake¶

CREATE TABLE table1 (
    col1 STRING
)
DEFAULT_DDL_COLLATION='und-ci';

Labels table option¶

BigQuery¶

CREATE TABLE table1
(
  col1 INT,
  col2 DATE
)
OPTIONS(
  labels=[("org_unit", "development")]
);

Snowflake¶

CREATE TAG IF NOT EXISTS "org_unit";

CREATE TABLE table1
(
  col1 INT,
  col2 DATE
)
WITH TAG( "org_unit" = "development" )
COMMENT = '{ "origin": "sf_sc", "name": "snowconvert", "version": {  "major": 0,  "minor": 0,  "patch": "0" }, "attributes": {  "component": "bigquery",  "convertedOn": "04/09/2025",  "domain": "test" }}'
;

Description table option¶

BigQuery¶

CREATE TABLE table1
(
  col1 INT,
  col2 DATE
)
OPTIONS(
  description = 'My table comment'
);

Snowflake¶

CREATE TABLE table1
(
  col1 INT,
  col2 DATE
)
COMMENT = '{ "description": "My table comment", "origin": "sf_sc", "name": "snowconvert", "version": {  "major": 0,  "minor": 0,  "patch": "0" }, "attributes": {  "component": "bigquery",  "convertedOn": "04/09/2025",  "domain": "test" }}'
;

Description table option¶

BigQuery¶

CREATE TABLE table1
(
  col1 INT,
  col2 DATE
)
OPTIONS(
  friendly_name = 'Some_table'
);

Snowflake¶

CREATE TABLE table1
(
  col1 INT,
  col2 DATE
)
COMMENT = '{ "friendly_name": "Some_table", "origin": "sf_sc", "name": "snowconvert", "version": {  "major": 0,  "minor": 0,  "patch": "0" }, "attributes": {  "component": "bigquery",  "convertedOn": "04/09/2025",  "domain": "test" }}'
;

Known Issues¶

1. Unsupported table options

Not all table options are supported in Snowflake, when an unsupported table option is encountered in the OPTIONS clause, an EWI will be generated to warn about this.

BigQuery¶

 CREATE TABLE table1
(
  col1 INT,
  col2 DATE
)
OPTIONS(
  expiration_timestamp=TIMESTAMP "2025-01-01 00:00:00 UTC",
  partition_expiration_days=1,
  description="a table that expires in 2025, with each partition living for 24 hours",
  labels=[("org_unit", "development")]
);

Snowflake¶

 CREATE TAG IF NOT EXISTS "org_unit";

CREATE TABLE table1
(
  col1 INT,
  col2 DATE
)
WITH TAG( "org_unit" = "development" )
!!!RESOLVE EWI!!! /*** SSC-EWI-BQ0001 - SNOWFLAKE DOES NOT SUPPORT THE OPTIONS: EXPIRATION_TIMESTAMP, PARTITION_EXPIRATION_DAYS. ***/!!!
OPTIONS(
  expiration_timestamp=TIMESTAMP "2025-01-01 00:00:00 UTC",
  partition_expiration_days=1
)
COMMENT = '{ "description": "a table that expires in 2025, with each partition living for 24 hours", "origin": "sf_sc", "name": "snowconvert", "version": {  "major": 0,  "minor": 0,  "patch": "0" }, "attributes": {  "component": "bigquery",  "convertedOn": "04/09/2025",  "domain": "test" }}'
;

2. Micro-partitioning is automatically managed by Snowflake

Snowflake performs automatic partitioning of data. User defined partitioning is not supported.

BigQuery¶

 CREATE TABLE table1(
    transaction_id INT, 
    transaction_date DATE
)
PARTITION BY transaction_date;

Snowflake¶

 CREATE TABLE table1 (
    transaction_id INT,
    transaction_date DATE
)
!!!RESOLVE EWI!!! /*** SSC-EWI-BQ0002 - MICRO-PARTITIONING IS AUTOMATICALLY PERFORMED ON ALL SNOWFLAKE TABLES. ***/!!!
PARTITION BY transaction_date;

COLUMN DEFINITION¶

Grammar syntax¶

 column :=
  column_name column_schema

column_schema :=
   {
     simple_type
     | STRUCT<field_list>
     | ARRAY<array_element_schema>
   }
   [PRIMARY KEY NOT ENFORCED | REFERENCES table_name(column_name) NOT ENFORCED]
   [DEFAULT default_expression]
   [NOT NULL]
   [OPTIONS(column_option_list)]

simple_type :=
  { data_type | STRING COLLATE collate_specification }

field_list :=
  field_name column_schema [, ...]

array_element_schema :=
  { simple_type | STRUCT<field_list> }
  [NOT NULL]

Sample Source Patterns¶

Description option¶

BigQuery¶

CREATE TABLE table1 (
  col1 VARCHAR(20) OPTIONS(description="A repeated STRING field")
);

Snowflake¶

CREATE TABLE table1 (
  col1 VARCHAR(20) COMMENT = 'A repeated STRING field'
);

COLLATE¶

BigQuery¶

CREATE TABLE table1 (
  col1 STRING COLLATE 'und:ci'
);

Snowflake¶

CREATE TABLE table1 (
  col1 STRING COLLATE 'und-ci'
);

Known Issues¶

1. Rounding mode not supported

Snowflake does not support specifying a default rounding mode on columns.

BigQuery¶

CREATE TABLE table1 (
  col1 STRING OPTIONS(rounding_mode = "ROUND_HALF_EVEN")
);

Snowflake¶

CREATE TABLE table1 (
    col1 STRING
    !!!RESOLVE EWI!!! /*** SSC-EWI-BQ0001 - SNOWFLAKE DOES NOT SUPPORT THE OPTIONS: ROUNDING_MODE. ***/!!!
    OPTIONS(
        rounding_mode = "ROUND_HALF_EVEN"
    )
)

Related EWIs¶

SSC-EWI-BQ0001: Snowflake does not support the options clause.

CREATE EXTERNAL TABLE¶

Description¶

External tables let BigQuery query data that is stored outside of BigQuery storage. (BigQuery SQL Language Reference CREATE EXTERNAL TABLE)

Syntax

CREATE [ OR REPLACE ] EXTERNAL TABLE [ IF NOT EXISTS ] table_name
[(
  column_name column_schema,
  ...
)]
[WITH CONNECTION {connection_name | DEFAULT}]
[WITH PARTITION COLUMNS
  [(
      partition_column_name partition_column_type,
      ...
  )]
]
OPTIONS (
  external_table_option_list,
  ...
);

The CREATE EXTERNAL TABLE statement from BigQuery will be transformed to a CREATE EXTERNAL TABLE statement from Snowflake, however, this transformation requires user intervention.

To complete the transformation performed by SnowConvert AI, it is necessary to define a Storage Integration, a External Stage and (optional) Notification Integration that have access to the external source were files are located. Please refer to the following guides on how to set up the connection for each provider:

Important considerations for the transformations shown in this page:

The @EXTERNAL_STAGE placeholder must be replaced with the external stage created after following the previous guide.
It is assumed that the external stage will point to the root of the bucket. This is important to consider because the PATTERN clause generated for each table specifies the file/folder paths starting at the base of the bucket, defining the external stage pointing to a different location in the bucket might produce undesired behavior.
The AUTO_REFRESH = FALSE clause is generated to avoid errors, please note that automatic refresh of external table metadata is only valid if your Snowflake account cloud provider and the bucket provider are the same and a Notification Integration was created.

Sample Source Patterns¶

CREATE EXTERNAL TABLE with explicit column list¶

When the column list is provided, SnowConvert AI will automatically generate the AS expression column options for each column to extract the file values.

BigQuery¶

 CREATE OR REPLACE EXTERNAL TABLE test.Employees_test
(
  Employee_id INTEGER,
  Name STRING,
  Mail STRING,
  Position STRING,
  Salary INTEGER
)
OPTIONS(
  FORMAT='CSV',
  SKIP_LEADING_ROWS=1,
  URIS=['gs://sc_external_table_bucket/folder_with_csv/Employees.csv']
);

Snowflake¶

 CREATE OR REPLACE EXTERNAL TABLE test.Employees_test
(
  Employee_id INTEGER AS CAST(GET_IGNORE_CASE($1, 'c1') AS INTEGER),
  Name STRING AS CAST(GET_IGNORE_CASE($1, 'c2') AS STRING),
  Mail STRING AS CAST(GET_IGNORE_CASE($1, 'c3') AS STRING),
  Position STRING AS CAST(GET_IGNORE_CASE($1, 'c4') AS STRING),
  Salary INTEGER AS CAST(GET_IGNORE_CASE($1, 'c5') AS INTEGER)
)
!!!RESOLVE EWI!!! /*** SSC-EWI-BQ0015 - EXTERNAL TABLE REQUIRES AN EXTERNAL STAGE TO ACCESS gs://sc_external_table_bucket, DEFINE AND REPLACE THE EXTERNAL_STAGE PLACEHOLDER ***/!!!
LOCATION = @EXTERNAL_STAGE
AUTO_REFRESH = false
PATTERN = 'folder_with_csv/Employees.csv'
FILE_FORMAT = (TYPE = CSV SKIP_HEADER =1);

CREATE EXTERNAL TABLE without explicit column list¶

When the column list is not provided, BigQuery automatically detects the schema of the columns from the file structure. To replicate this behavior, SnowConvert AI will generate a USING TEMPLATE clause that makes use of the INFER_SCHEMA function to generate the column definitions.

Since the INFER_SCHEMA function requires a file format to work, SnowConvert AI will generate a temporary file format for this purpose, this file format is only required when running the CREATE EXTERNAL TABLE statement and it will be automatically dropped when the session ends.

BigQuery¶

 CREATE OR REPLACE EXTERNAL TABLE test.my_external_table_json
OPTIONS(
  FORMAT='JSON',
  URIS=['gs://sc_external_table_bucket/folder_with_json/Cars.jsonl']
);

Snowflake¶

CREATE OR REPLACE TEMPORARY FILE FORMAT SC_TEST_MY_EXTERNAL_TABLE_JSON_FORMAT
TYPE = JSON;

CREATE OR REPLACE EXTERNAL TABLE test.my_external_table_json USING TEMPLATE (
SELECT
  ARRAY_AGG(OBJECT_CONSTRUCT('COLUMN_NAME', COLUMN_NAME, 'TYPE', TYPE, 'NULLABLE', NULLABLE, 'EXPRESSION', EXPRESSION))
FROM
  TABLE(INFER_SCHEMA(LOCATION => '@EXTERNAL_STAGE/folder_with_json/Cars.jsonl', FILE_FORMAT => 'SC_TEST_MY_EXTERNAL_TABLE_JSON_FORMAT'))
)
!!!RESOLVE EWI!!! /*** SSC-EWI-BQ0015 - EXTERNAL TABLE REQUIRES AN EXTERNAL STAGE TO ACCESS gs://sc_external_table_bucket, DEFINE AND REPLACE THE EXTERNAL_STAGE PLACEHOLDER ***/!!!
LOCATION = @EXTERNAL_STAGE
AUTO_REFRESH = false
PATTERN = 'folder_with_json/Cars.jsonl'
FILE_FORMAT = (TYPE = JSON);

CREATE EXTERNAL TABLE with multiple URIs¶

When multiple source URIs are specified, they will be joined in the regex of the PATTERN clause in Snowflake, the wildcard * characters used will be transformed to its .* equivalent in Snowflake.

BigQuery¶

 CREATE OR REPLACE EXTERNAL TABLE test.multipleFilesTable
(
  Name STRING,
  Code STRING,
  Price NUMERIC,
  Expiration_date DATE
)

OPTIONS(
  format="CSV",
  skip_leading_rows = 1,
  uris=['gs://sc_external_table_bucket/folder_with_csv/Food.csv', 'gs://sc_external_table_bucket/folder_with_csv/other_products/*']
);

Snowflake¶

 CREATE OR REPLACE EXTERNAL TABLE test.multipleFilesTable
(
  Name STRING AS CAST(GET_IGNORE_CASE($1, 'c1') AS STRING),
  Code STRING AS CAST(GET_IGNORE_CASE($1, 'c2') AS STRING),
  Price NUMERIC AS CAST(GET_IGNORE_CASE($1, 'c3') AS NUMERIC),
  Expiration_date DATE AS CAST(GET_IGNORE_CASE($1, 'c4') AS DATE)
)
!!!RESOLVE EWI!!! /*** SSC-EWI-BQ0015 - EXTERNAL TABLE REQUIRES AN EXTERNAL STAGE TO ACCESS gs://sc_external_table_bucket, DEFINE AND REPLACE THE EXTERNAL_STAGE PLACEHOLDER ***/!!!
LOCATION = @EXTERNAL_STAGE
AUTO_REFRESH = false
PATTERN = 'folder_with_csv/Food.csv|folder_with_csv/other_products/.*'
FILE_FORMAT = (TYPE = CSV SKIP_HEADER = 1);

WITH CONNECTION clause¶

The WITH CONNECTION clause is removed because the connection information is already provided to Snowflake using the Storage Integration.

BigQuery¶

 CREATE EXTERNAL TABLE test.awsTable
  WITH CONNECTION `aws-us-east-1.s3-read-connection`
  OPTIONS (
    format="JSON",
    uris=["s3://s3-bucket/json_files/example.jsonl"]
);

Snowflake¶

CREATE OR REPLACE TEMPORARY FILE FORMAT SC_TEST_AWSTABLE_FORMAT
TYPE = JSON;

CREATE EXTERNAL TABLE test.awsTable USING TEMPLATE (
SELECT
  ARRAY_AGG(OBJECT_CONSTRUCT('COLUMN_NAME', COLUMN_NAME, 'TYPE', TYPE, 'NULLABLE', NULLABLE, 'EXPRESSION', EXPRESSION))
FROM
  TABLE(INFER_SCHEMA(LOCATION => '@EXTERNAL_STAGE/json_files/example.jsonl', FILE_FORMAT => 'SC_TEST_AWSTABLE_FORMAT'))
)
!!!RESOLVE EWI!!! /*** SSC-EWI-BQ0015 - EXTERNAL TABLE REQUIRES AN EXTERNAL STAGE TO ACCESS s3://s3-bucket, DEFINE AND REPLACE THE EXTERNAL_STAGE PLACEHOLDER ***/!!!
LOCATION = @EXTERNAL_STAGE
AUTO_REFRESH = false
PATTERN = 'json_files/example.jsonl'
FILE_FORMAT = (TYPE = JSON);

Supported table options¶

The following external table options are supported in Snowflake and transformed by SnowConvert AI:

FORMAT
ENCODING
SKIP_LEADING_ROWS
FIELD_DELIMITER
COMPRESSION

BigQuery¶

CREATE OR REPLACE EXTERNAL TABLE test.songs_test
(
  Name STRING,
  Release_date INTEGER,
  Songs INT,
  Genre STRING
)
OPTIONS(
  FORMAT='CSV',
  ENCODING='UTF-8',
  SKIP_LEADING_ROWS=1,
  FIELD_DELIMITER='|',
  COMPRESSION='GZIP',
  URIS=['gs://sc_external_table_bucket/folder_with_csv/Albums.csv']
);

Snowflake¶

CREATE OR REPLACE EXTERNAL TABLE test.songs_test
(
  Name STRING AS CAST(GET_IGNORE_CASE($1, 'c1') AS STRING),
  Release_date INTEGER AS CAST(GET_IGNORE_CASE($1, 'c2') AS INTEGER),
  Songs INT AS CAST(GET_IGNORE_CASE($1, 'c3') AS INT),
  Genre STRING AS CAST(GET_IGNORE_CASE($1, 'c4') AS STRING)
)
!!!RESOLVE EWI!!! /*** SSC-EWI-BQ0015 - EXTERNAL TABLE REQUIRES AN EXTERNAL STAGE TO ACCESS gs://sc_external_table_bucket, DEFINE AND REPLACE THE EXTERNAL_STAGE PLACEHOLDER ***/!!!
LOCATION = @EXTERNAL_STAGE
AUTO_REFRESH = false
PATTERN = 'folder_with_csv/Albums.csv'
FILE_FORMAT = (TYPE = CSV
  ENCODING= 'UTF8' SKIP_HEADER =1
  FIELD_DELIMITER='|'
  COMPRESSION= GZIP);

Known Issues¶

1. CREATE EXTERNAL TABLE without explicit column list and CSV file format

Currently, Snowflake external tables do not support parsing the header of CSV files. When an external table with no explicit column list and CSV file format is found, SnowConvert AI will produce the SKIP_HEADER file format option to avoid runtime errors, however, this will cause the table column names to have the autogenerated names c1, c2, …, cN.

An FDM is generated to notify that the header can not be parsed and that manually renaming the columns is necessary to preserve the names.

BigQuery¶

 CREATE OR REPLACE EXTERNAL TABLE test.my_external_table_csv
OPTIONS(
  FORMAT='CSV',
  URIS=['gs://sc_external_table_bucket/folder_with_csv/Employees.csv']
);

Snowflake¶

CREATE OR REPLACE TEMPORARY FILE FORMAT SC_TEST_MY_EXTERNAL_TABLE_CSV_FORMAT
TYPE = CSV
SKIP_HEADER = 1;

CREATE OR REPLACE EXTERNAL TABLE test.my_external_table_csv
--** SSC-FDM-BQ0005 - PARSING THE CSV HEADER IS NOT SUPPORTED IN EXTERNAL TABLES, COLUMNS MUST BE RENAMED TO MATCH THE ORIGINAL NAMES **
USING TEMPLATE (
SELECT
  ARRAY_AGG(OBJECT_CONSTRUCT('COLUMN_NAME', COLUMN_NAME, 'TYPE', TYPE, 'NULLABLE', NULLABLE, 'EXPRESSION', EXPRESSION))
FROM
  TABLE(INFER_SCHEMA(LOCATION => '@EXTERNAL_STAGE/folder_with_csv/Employees.csv', FILE_FORMAT => 'SC_TEST_MY_EXTERNAL_TABLE_CSV_FORMAT'))
)
!!!RESOLVE EWI!!! /*** SSC-EWI-BQ0015 - EXTERNAL TABLE REQUIRES AN EXTERNAL STAGE TO ACCESS gs://sc_external_table_bucket, DEFINE AND REPLACE THE EXTERNAL_STAGE PLACEHOLDER ***/!!!
LOCATION = @EXTERNAL_STAGE
AUTO_REFRESH = false
PATTERN = 'folder_with_csv/Employees.csv'
FILE_FORMAT = (TYPE = CSV SKIP_HEADER = 1);

2. External tables referencing Google Drive sources

Snowflake does not support reading data from files hosted in Google Drive, an FDM will be generated to notify about this and request that the files are uploaded to the bucket and accessed through the external stage.

The PATTERN clause will hold autogenerated placeholders FILE_PATH0, FILE_PATH1, …, FILE_PATHN that should be replaced with the file/folder path after the files were moved to the external location.

BigQuery¶

 CREATE OR REPLACE EXTERNAL TABLE test.my_external_table_drive_test
OPTIONS(
  FORMAT='JSON',
  URIS=['https://drive.google.com/open?id=someFileId']
);

Snowflake¶

 CREATE OR REPLACE TEMPORARY FILE FORMAT SC_TEST_MY_EXTERNAL_TABLE_DRIVE_TEST_FORMAT
TYPE = JSON;

CREATE OR REPLACE EXTERNAL TABLE test.my_external_table_drive_test USING TEMPLATE (
SELECT
  ARRAY_AGG(OBJECT_CONSTRUCT('COLUMN_NAME', COLUMN_NAME, 'TYPE', TYPE, 'NULLABLE', NULLABLE, 'EXPRESSION', EXPRESSION))
FROM
  --** SSC-FDM-BQ0008 - THE INFER_SCHEMA FUNCTION REQUIRES A FILE PATH WITHOUT WILDCARDS TO GENERATE THE TABLE TEMPLATE, REPLACE THE FILE_PATH PLACEHOLDER WITH IT **
  TABLE(INFER_SCHEMA(LOCATION => '@EXTERNAL_STAGE/FILE_PATH', FILE_FORMAT => 'SC_TEST_MY_EXTERNAL_TABLE_DRIVE_TEST_FORMAT'))
)
!!!RESOLVE EWI!!! /*** SSC-EWI-BQ0015 - EXTERNAL TABLE REQUIRES AN EXTERNAL STAGE TO ACCESS A EXTERNAL LOCATION, DEFINE AND REPLACE THE EXTERNAL_STAGE PLACEHOLDER ***/!!!
LOCATION = @EXTERNAL_STAGE
AUTO_REFRESH = false
--** SSC-FDM-BQ0006 - READING FROM GOOGLE DRIVE IS NOT SUPPORTED IN SNOWFLAKE, UPLOAD THE FILES TO THE EXTERNAL LOCATION AND REPLACE THE FILE_PATH PLACEHOLDERS **
PATTERN = 'FILE_PATH0'
FILE_FORMAT = (TYPE = JSON);

3. External tables with the GOOGLE_SHEETS file format

Snowflake does not support Google Sheets as a file format, however, its structure is similar to CSV files, which are supported by Snowflake.

When SnowConvert AI detects an external table using the GOOGLE_SHEETS format, it will produce an external table with the CSV file format instead.

Since Google Sheets are stored in Google Drive, it would be necessary to upload the files as CSV to the external location and specify the file paths in the PATTERN clause, just as mentioned in the previous issue.

BigQuery¶

 CREATE OR REPLACE EXTERNAL TABLE test.spreadsheetTable
(
  Name STRING,
  Code INTEGER,
  Price INTEGER,
  Expiration_date DATE
)
OPTIONS(
  format="GOOGLE_SHEETS",
  skip_leading_rows = 1,
  uris=['https://docs.google.com/spreadsheets/d/someFileId/edit?usp=sharing']
);

Snowflake¶

 --** SSC-FDM-BQ0007 - THE GOOGLE_SHEETS FORMAT IS NOT SUPPORTED IN SNOWFLAKE. CSV FILE TYPE IS USED AS A WORKAROUND. **
CREATE OR REPLACE EXTERNAL TABLE test.spreadsheetTable
(
  Name STRING AS CAST(GET_IGNORE_CASE($1, 'c1') AS STRING),
  Code INTEGER AS CAST(GET_IGNORE_CASE($1, 'c2') AS INTEGER),
  Price INTEGER AS CAST(GET_IGNORE_CASE($1, 'c3') AS INTEGER),
  Expiration_date DATE AS CAST(GET_IGNORE_CASE($1, 'c4') AS DATE)
)
!!!RESOLVE EWI!!! /*** SSC-EWI-BQ0015 - EXTERNAL TABLE REQUIRES AN EXTERNAL STAGE TO ACCESS A EXTERNAL LOCATION, DEFINE AND REPLACE THE EXTERNAL_STAGE PLACEHOLDER ***/!!!
LOCATION = @EXTERNAL_STAGE
AUTO_REFRESH = false
--** SSC-FDM-BQ0006 - READING FROM GOOGLE DRIVE IS NOT SUPPORTED IN SNOWFLAKE, UPLOAD THE FILES TO THE EXTERNAL LOCATION AND REPLACE THE FILE_PATH PLACEHOLDERS **
PATTERN = 'FILE_PATH0'
FILE_FORMAT = (TYPE = CSV SKIP_HEADER = 1);

4. External tables with unsupported file formats

Snowflake supports the following BigQuery formats:


BigQuery	Snowflake
AVRO	AVRO
CSV GOOGLE_SHEETS	CSV
NEWLINE_DELIMITED_JSON JSON	JSON
ORC	ORC
PARQUET	PARQUET

Other formats will be marked as not supported.

BigQuery¶

 CREATE OR REPLACE EXTERNAL TABLE test.backup_restore_table
OPTIONS (
  format = 'DATASTORE_BACKUP',
  uris = ['gs://backup_bucket/backup_folder/*']
);

Snowflake¶

 !!!RESOLVE EWI!!! /*** SSC-EWI-BQ0013 - EXTERNAL TABLE DATA FORMAT NOT SUPPORTED IN SNOWFLAKE ***/!!!
CREATE OR REPLACE EXTERNAL TABLE test.backup_restore_table
OPTIONS (
  format = 'DATASTORE_BACKUP',
  uris = ['gs://backup_bucket/backup_folder/*']
);

5. Hive partitioned external tables

Snowflake does not support hive partitioned external tables, the WITH PARTITION COLUMNS clause will be marked as not supported.

BigQuery¶

CREATE EXTERNAL TABLE test.CustomHivePartitionedTable
WITH PARTITION COLUMNS (
  field_1 STRING,
  field_2 INT64)
OPTIONS (
  uris = ['gs://sc_external_table_bucket/folder_with_parquet/*'],
  format = 'PARQUET',
  hive_partition_uri_prefix = 'gs://sc_external_table_bucket/folder_with_parquet',
  require_hive_partition_filter = false);

Snowflake¶

CREATE OR REPLACE TEMPORARY FILE FORMAT SC_TEST_CUSTOMHIVEPARTITIONEDTABLE_FORMAT
TYPE = PARQUET;

CREATE EXTERNAL TABLE test.CustomHivePartitionedTable USING TEMPLATE (
SELECT
  ARRAY_AGG(OBJECT_CONSTRUCT('COLUMN_NAME', COLUMN_NAME, 'TYPE', TYPE, 'NULLABLE', NULLABLE, 'EXPRESSION', EXPRESSION))
FROM
  --** SSC-FDM-BQ0008 - THE INFER_SCHEMA FUNCTION REQUIRES A FILE PATH WITHOUT WILDCARDS TO GENERATE THE TABLE TEMPLATE, REPLACE THE FILE_PATH PLACEHOLDER WITH IT **
  TABLE(INFER_SCHEMA(LOCATION => '@EXTERNAL_STAGE/FILE_PATH', FILE_FORMAT => 'SC_TEST_CUSTOMHIVEPARTITIONEDTABLE_FORMAT'))
)
!!!RESOLVE EWI!!! /*** SSC-EWI-BQ0015 - EXTERNAL TABLE REQUIRES AN EXTERNAL STAGE TO ACCESS gs://sc_external_table_bucket, DEFINE AND REPLACE THE EXTERNAL_STAGE PLACEHOLDER ***/!!!
LOCATION = @EXTERNAL_STAGE
AUTO_REFRESH = false
!!!RESOLVE EWI!!! /*** SSC-EWI-BQ0014 - HIVE PARTITIONED EXTERNAL TABLES ARE NOT SUPPORTED IN SNOWFLAKE ***/!!!
WITH PARTITION COLUMNS (
  field_1 STRING,
  field_2 INT64)
PATTERN = 'folder_with_parquet/.*'
FILE_FORMAT = (TYPE = PARQUET)
!!!RESOLVE EWI!!! /*** SSC-EWI-BQ0001 - SNOWFLAKE DOES NOT SUPPORT THE OPTIONS: HIVE_PARTITION_URI_PREFIX, REQUIRE_HIVE_PARTITION_FILTER. ***/!!!
OPTIONS(
  hive_partition_uri_prefix = 'gs://sc_external_table_bucket/folder_with_parquet',
  require_hive_partition_filter = false
);

6. External table without columns list and no valid file URI for the INFER_SCHEMA function

The INFER_SCHEMA function requires a LOCATION parameter that specifies the path to a file or folder that will be used to construct the table columns, however, this path does not support regex, meaning that the wildcard * character is not supported.

When the table has no columns, SnowConvert AI will check all URIS to find one that does not use wildcards and use it in the INFER_SCHEMA function, when no URI meets such criteria an FDM and FILE_PATH placeholder will be generated, the placeholder has to be replaced with the path of one of the files referenced by the external table to generate the table columns.

BigQuery¶

CREATE OR REPLACE EXTERNAL TABLE test.my_external_table_json2
OPTIONS(
  FORMAT='JSON',
  URIS=['gs://sc_external_table_bucket/folder_with_json/*']
);

Snowflake¶

CREATE OR REPLACE TEMPORARY FILE FORMAT SC_TEST_MY_EXTERNAL_TABLE_JSON2_FORMAT
TYPE = JSON;

CREATE OR REPLACE EXTERNAL TABLE test.my_external_table_json2 USING TEMPLATE (
SELECT
  ARRAY_AGG(OBJECT_CONSTRUCT('COLUMN_NAME', COLUMN_NAME, 'TYPE', TYPE, 'NULLABLE', NULLABLE, 'EXPRESSION', EXPRESSION))
FROM
  --** SSC-FDM-BQ0008 - THE INFER_SCHEMA FUNCTION REQUIRES A FILE PATH WITHOUT WILDCARDS TO GENERATE THE TABLE TEMPLATE, REPLACE THE FILE_PATH PLACEHOLDER WITH IT **
  TABLE(INFER_SCHEMA(LOCATION => '@EXTERNAL_STAGE/FILE_PATH', FILE_FORMAT => 'SC_TEST_MY_EXTERNAL_TABLE_JSON2_FORMAT'))
)
!!!RESOLVE EWI!!! /*** SSC-EWI-BQ0015 - EXTERNAL TABLE REQUIRES AN EXTERNAL STAGE TO ACCESS gs://sc_external_table_bucket, DEFINE AND REPLACE THE EXTERNAL_STAGE PLACEHOLDER ***/!!!
LOCATION = @EXTERNAL_STAGE
AUTO_REFRESH = false
PATTERN = 'folder_with_json/.*'
FILE_FORMAT = (TYPE = JSON);

7. Unsupported table options

Any other table option not mentioned in the Supported table options pattern will be marked as not supported.

BigQuery¶

CREATE OR REPLACE EXTERNAL TABLE dataset.CsvTable
(
  x INTEGER,
  y STRING
)
OPTIONS (
  format = 'CSV',
  uris = ['gs://bucket/example.csv'],
  field_delimiter = '|',
  max_bad_records = 5
);

Snowflake¶

CREATE OR REPLACE EXTERNAL TABLE dataset.CsvTable
(
  x INTEGER AS CAST(GET_IGNORE_CASE($1, 'c1') AS INTEGER),
  y STRING AS CAST(GET_IGNORE_CASE($1, 'c2') AS STRING)
)
!!!RESOLVE EWI!!! /*** SSC-EWI-BQ0015 - EXTERNAL TABLE REQUIRES AN EXTERNAL STAGE TO ACCESS gs://bucket, DEFINE AND REPLACE THE EXTERNAL_STAGE PLACEHOLDER ***/!!!
LOCATION = @EXTERNAL_STAGE
AUTO_REFRESH = false
PATTERN = 'example.csv'
FILE_FORMAT = (TYPE = CSV
  field_delimiter = '|')
!!!RESOLVE EWI!!! /*** SSC-EWI-BQ0001 - SNOWFLAKE DOES NOT SUPPORT THE OPTIONS: MAX_BAD_RECORDS. ***/!!!
OPTIONS(
  max_bad_records = 5
);

Related EWIs¶

SSC-EWI-BQ0013: External table data format not supported in snowflake
SSC-EWI-BQ0014: Hive partitioned external tables are not supported in snowflake
SSC-EWI-BQ0015: External table requires an external stage to access an external location, define and replace the EXTERNAL_STAGE placeholder
SSC-FDM-BQ0004: The INFER_SCHEMA function requires a file path without wildcards to generate the table template, replace the FILE_PATH placeholder with it
SSC-FDM-BQ0005: Parsing the CSV header is not supported in external tables, columns must be renamed to match the original names
SSC-FDM-BQ0006: Reading from Google Drive is not supported in Snowflake, upload the files to the external location and replace the FILE_PATH placeholders
SSC-FDM-BQ0007: The GOOGLE_SHEETS format is not supported in Snowflake. CSV file type is used as a workaround.

CREATE TABLE CLONE¶

Grammar syntax¶

CREATE TABLE [ IF NOT EXISTS ]
destination_table_name
CLONE source_table_name [FOR SYSTEM_TIME AS OF time_expression]
...
[OPTIONS(table_option_list)]

Sample Source Patterns¶

FOR SYSTEM TIME AS OF¶

BigQuery¶

CREATE TABLE my_clone_table
CLONE some_table_name2
FOR SYSTEM_TIME AS OF TIMESTAMP "2025-01-01 00:00:00 UTC";

Snowflake¶

CREATE TABLE my_clone_table
CLONE some_table_name2 AT (TIMESTAMP => TIMESTAMP "2025-01-01 00:00:00 UTC");

::{note} The LABELS option in CREATE TABLE CLONE statements are not transformed into TAGs because the TAGs of the source table are copied, they cannot be changed during the copy of the table. Transformation of other table options are the same as specified for the CREATE TABLE statement.

CREATE TABLE COPY

Grammar syntax

CREATE [ OR REPLACE ] TABLE [ IF NOT EXISTS ] table_name
COPY source_table_name
...
[OPTIONS(table_option_list)]

Sample Source Patterns

General case

CREATE TABLE CLONE in Snowflake is functionally equivalent to CREATE TABLE COPY.

Input Code

BigQuery

CREATE TABLE newtable
COPY sourceTable;

Snowflake

CREATE TABLE newtable CLONE sourceTable;

Note

The LABELS option in CREATE TABLE COPY statements are not transformed into TAGs because the TAGs of the source table are copied, they cannot be changed during the copy of the table. Transformation of other table options are the same as specified for the CREATE TABLE statement.

CREATE TABLE LIKE¶

Grammar syntax¶

CREATE [ OR REPLACE ] TABLE [ IF NOT EXISTS ]
table_name
LIKE [[project_name.]dataset_name.]source_table_name
...
[OPTIONS(table_option_list)]

Success

CREATE TABLE LIKE is fully supported by Snowflake.

Note

The LABELS option in CREATE TABLE LIKE statements are not transformed into TAGs because the TAGs of the source table are copied, they cannot be changed during the copy of the table. Transformation of other table options are the same as specified for the CREATE TABLE statement.

CREATE TABLE SNAPSHOT¶

Grammar syntax¶

CREATE SNAPSHOT TABLE [ IF NOT EXISTS ] table_snapshot_name
CLONE source_table_name
[FOR SYSTEM_TIME AS OF time_expression]
[OPTIONS(snapshot_option_list)]

Sample Source Patterns¶

General case¶

The Snapshot keyword is removed in Snowflake, transforming the table into a CREATE TABLE CLONE.

The two differences between snapshot and clones are that snapshots are not editable and usually have an expiration date. Expiration dates are not supported, this is handled as specified for the CREATE TABLE statement unsupported options.

BigQuery¶

CREATE SNAPSHOT TABLE mytablesnapshot
CLONE mytable;

Snowflake¶

CREATE TABLE mytablesnapshot CLONE mytable;

FOR SYSTEM TIME AS OF¶

BigQuery¶

CREATE SNAPSHOT TABLE IF NOT EXISTS my_snapshot_table2
CLONE some_table_name2
FOR SYSTEM_TIME AS OF TIMESTAMP "2025-01-01 00:00:00 UTC";

Snowflake¶

CREATE TABLE IF NOT EXISTS my_snapshot_table2
CLONE some_table_name2 AT (TIMESTAMP => TIMESTAMP "2025-01-01 00:00:00 UTC");

Note

The LABELS option in CREATE TABLE COPY statements are not transformed into TAGs because the TAGs of the source table are copied, they cannot be changed during the copy of the table.

Transformation of other table options are the same as specified for the CREATE TABLE statement.