Statements

ReferenceApplies to: Unified engine deployments

Use statements to inspect objects, define tables and views, and change data. Commands run in a session; a script stops at its first failed statement. Connector capabilities determine which table definitions and mutations can be committed.

Statement families

Family	Forms	Reference
Query	SELECT, WITH, VALUES, UNION, INTERSECT, EXCEPT	Queries
Inspect	SHOW CATALOGS, SHOW NAMESPACES, SHOW TABLES, DESCRIBE TABLE, SHOW CREATE TABLE, SHOW TBLPROPERTIES	This page
Objects	CREATE, ALTER, DROP TABLE/VIEW; catalog and namespace commands	Tables and sources
Access	CREATE, ALTER, DROP, SHOW, DESCRIBE SECRET/CREDENTIAL	Secrets, credentials
Write	INSERT INTO, INSERT OVERWRITE, UPDATE, DELETE, MERGE, TRUNCATE TABLE	Writing data
Maintenance	CALL	Maintenance

Discover objects

The following script selects the configured example catalog and namespace before discovery. The last statement supplies the displayed result. Run a statement separately to inspect its own output.

USE CATALOG demo;
USE tpcds;
SHOW TABLES;

SHOW CATALOGS;

DESCRIBE TABLE demo.tpcds.item;

SHOW CREATE TABLE demo.tpcds.item;

SHOW TBLPROPERTIES is recognized by the language but is currently rejected by the SQL operation service. Use the table detail page to inspect properties. DESCRIBE returns column information. SHOW CREATE TABLE reconstructs a definition from available metadata; provider-specific details can make that reconstruction incomplete. Property discovery is separate from reading data rows.

Catalogs and namespaces

A catalog registers a metadata provider and its connection options. A namespace groups tables and views within that catalog. USE changes the current session context; it does not move data.

Form	Behavior
`CREATE CATALOG name USING provider OPTIONS (...)`	Register a supported catalog provider; options and named credentials must satisfy its contract.
`ALTER CATALOG name ...`	Set or unset supported connection options or credential references.
`DROP CATALOG name`	Remove a registration subject to service rules.
`CREATE NAMESPACE catalog.namespace`	Create an object namespace in a catalog that supports it.
`ALTER NAMESPACE ...`	Change supported namespace metadata.
`DROP NAMESPACE ...`	Remove a namespace according to catalog rules.
`SHOW NAMESPACES`	List namespaces in the current catalog.

DATABASE and SCHEMA have supported namespace spellings. Register Hub’s Lakekeeper connection and its MinIO access in Catalogs, then select that catalog in your SQL client. See Hub setup.

USE CATALOG demo;
SHOW NAMESPACES;

Definitions and changes

CREATE TABLE accepts an explicit schema or AS SELECT. USING, OPTIONS, PARTITIONED BY, LOCATION, COMMENT, and TBLPROPERTIES describe the provider, layout, and metadata. IF NOT EXISTS avoids a name collision; it does not check that an existing table matches the requested definition. ALTER TABLE supports specific schema and property changes; it is not a promise that every Spark schema-evolution command is available. DROP removes an object according to its catalog semantics. Examples that create and remove objects are confined to the write lab.

Secrets and credentials

Named secrets and credentials have CREATE, ALTER, DROP, SHOW, and DESCRIBE SQL forms. A secret can hold a literal or an external reference; a credential identifies a provider and named options or secrets. Sensitive SQL is hidden in history and audit output. Use the product’s Access pages to create and inspect these resources without putting secret values in shared examples.

Resource	SQL management	HTTP management
Secrets	CREATE, ALTER, DROP SECRET; SHOW SECRETS; DESCRIBE SECRET	SQL through the session and operation API
Credentials	CREATE, ALTER, DROP CREDENTIAL; SHOW CREDENTIALS; DESCRIBE CREDENTIAL	SQL through the session and operation API
Catalog registrations	CREATE, ALTER, DROP CATALOG; SHOW CATALOGS	Dedicated catalog routes or SQL operations

See secret SQL and HTTP examples, credential SQL and HTTP examples, and catalog SQL and HTTP examples. There are no dedicated Unified secrets or credentials REST routes. SHOW and DESCRIBE for access resources return metadata and references, rather than secret values.

Unsupported commands

SHOW FUNCTIONS currently needs a function-catalog contract; use the searchable function inventory. CACHE TABLE, UNCACHE TABLE, CLEAR CACHE, and REFRESH need a cache service. ANALYZE TABLE, MSCK REPAIR TABLE, and SHOW PARTITIONS reach unsupported catalog-maintenance contracts. Syntax recognition alone does not make these commands executable.

Transformation Engine

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Workloads

SQL reference

HTTP API

Recipes

Operations

Statement families

Discover objects

Catalogs and namespaces

Definitions and changes

Secrets and credentials

Unsupported commands

​Statement families

​Discover objects

​Catalogs and namespaces

​Definitions and changes

​Secrets and credentials

​Unsupported commands

Statement families

Discover objects

Catalogs and namespaces

Definitions and changes

Secrets and credentials

Unsupported commands