> ## Documentation Index
> Fetch the complete documentation index at: https://docs.e6data.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Statements

> 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 determi

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](https://docs.e6data.com/transformation/sql/queries.md) |
| 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](https://docs.e6data.com/transformation/sql/tables-and-sources.md) |
| Access | CREATE, ALTER, DROP, SHOW, DESCRIBE SECRET/CREDENTIAL | [Secrets](https://docs.e6data.com/transformation/learn/secrets.md), [credentials](https://docs.e6data.com/transformation/learn/credentials.md) |
| Write | INSERT INTO, INSERT OVERWRITE, UPDATE, DELETE, MERGE, TRUNCATE TABLE | [Writing data](https://docs.e6data.com/transformation/sql/writes.md) |
| Maintenance | CALL | [Maintenance](https://docs.e6data.com/transformation/sql/maintenance.md) |

## 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.

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
USE CATALOG demo;
USE tpcds;
SHOW TABLES;
```

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
SHOW CATALOGS;
```

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
DESCRIBE TABLE demo.tpcds.item;
```

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
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.

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
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](https://docs.e6data.com/transformation/sql/tables-and-sources.md).

## 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](https://docs.e6data.com/transformation/learn/secrets.md), [credential SQL and HTTP examples](https://docs.e6data.com/transformation/learn/credentials.md), and [catalog SQL and HTTP examples](https://docs.e6data.com/transformation/learn/connect.md). 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](https://docs.e6data.com/transformation/sql/functions.md). 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.


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