> For the complete documentation index, see [llms.txt](https://docs.deltastream.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.deltastream.io/reference/sql-syntax/command/describe-relation-columns.md).

# DESCRIBE RELATION COLUMNS

## Syntax

```sql
DESCRIBE [ RELATION | STREAM | CHANGELOG | MATERIALIZED VIEW ]
COLUMNS fully_qualified_relation_name;
```

## Description

This provides the information about an existing [Database](/overview/core-concepts/databases.md#relation)'s columns in a [Database's](/overview/core-concepts/databases.md) [schema](/overview/core-concepts/databases.md#schema). This command can also be used to define a specific relation type's columns. See [LIST RELATIONS](/reference/sql-syntax/command/list-relations.md) for a list of available relations to describe.

Relations are visible only if the current [Access Control](/overview/core-concepts/access-control.md#role) has `USAGE` privileges on the database and schema and `SELECT` or `INSERT` privilege on the relation.

### Arguments <a href="#parameters" id="parameters"></a>

#### fully\_qualified\_relation\_name

This is the name of the relation to describe its columns. If the name is case-sensitive you must wrap it in double quotes; otherwise, the system uses the lowercase name.

Optionally, the relation name may be fully-qualified in the format of `<database_name>.<schema_name>.<relation_name>` or `<schema_name>.<relation_name>`. If the database or schema name is not provided, the system uses the current session's database or schema (see [USE](/reference/sql-syntax/command/use.md)).

## Examples

#### Describe a Stream's columns

```sh
demodb.public/demostore# DESCRIBE RELATION COLUMNS pageviews;
+----------+---------+-----------+-------------+
|  Name    |  Type   |  Nullable |  Properties |
+==========+=========+===========+=============+
| viewtime | BIGINT  | true      | {}          |
+----------+---------+-----------+-------------+
| userid   | VARCHAR | true      | {}          |
+----------+---------+-----------+-------------+
| pageid   | VARCHAR | true      | {}          |
+----------+---------+-----------+-------------+
```

#### Describe a stream's columns in a specific database/schema

The following describes the `total_views` [Database](/overview/core-concepts/databases.md#stream) relation columns in the `demodb` database and `analytics` schema, using its fully-qualified relation name:

```bash
demodb.public/demostore# DESCRIBE RELATION COLUMNS pageviews;
+----------+---------+-----------+-------------+
|  Name    |  Type   |  Nullable |  Properties |
+==========+=========+===========+=============+
| viewtime | BIGINT  | true      | {}          |
+----------+---------+-----------+-------------+
| userid   | VARCHAR | true      | {}          |
+----------+---------+-----------+-------------+
| pageid   | VARCHAR | true      | {}          |
+----------+---------+-----------+-------------+
```

#### Describe a materialized view's columns

The following describes the columns for `pvcount` in the `demodb` database and `public` schema:

```bash
demodb.public/demostore# DESCRIBE MATERIALIZED VIEW COLUMNS demodb."public".pvcount;
+-------------+---------+-----------+-------------+
|  Name       |  Type   |  Nullable |  Properties |
+=============+=========+===========+=============+
| page_name   | VARCHAR | true      | {}          |
+-------------+---------+-----------+-------------+
| pageid      | VARCHAR | true      | {}          |
+-------------+---------+-----------+-------------+
| cnt         | BIGINT  | false     | {}          |
+-------------+---------+-----------+-------------+
```

#### Describe a changelog

The following describes the `users_log` [Database](/overview/core-concepts/databases.md#changelog) in the current database and schema:

```bash
demodb.public/demostore# DESCRIBE CHANGELOG COLUMNS users_log;
+--------------+-----------------------+-----------+-------------+
|  Name        |  Type                 |  Nullable |  Properties |
+==============+=======================+===========+=============+
| registertime | BIGINT                | true      | {}          |
+--------------+-----------------------+-----------+-------------+
| userid       | VARCHAR               | true      | {}          |
+--------------+-----------------------+-----------+-------------+
| regionid     | VARCHAR               | true      | {}          |
+--------------+-----------------------+-----------+-------------+
| gender       | VARCHAR               | true      | {}          |
+--------------+-----------------------+-----------+-------------+
| interests    | ARRAY<VARCHAR>        | true      | {}          |
+--------------+-----------------------+-----------+-------------+
| contactinfo  | STRUCT <phone VARCHAR | true      | {}          |
|              | , city VARCHAR,       |           |             |
|              | "state" VARCHAR, zip  |           |             |
|              | code VARCHAR>         |           |             |
+--------------+-----------------------+-----------+-------------+
```

#### Describe a Table's columns

The following describes the columns for `pv_agg` [Database](/overview/core-concepts/databases.md#table) in the current database and schema:

```sh
demodb.public/demostore# DESCRIBE RELATION COLUMNS pv_agg;
+-----------+---------+-----------+-------------+
|  Name     |  Type   |  Nullable |  Properties |
+===========+=========+===========+=============+
| userid    | VARCHAR | true      | {}          |
+-----------+---------+-----------+-------------+
| pagecount | BIGINT  | true      | {}          |
+-----------+---------+-----------+-------------+
```

#### Describe a relation's columns with a case-sensitive name

The following describes the columns for `Pageviews` [Database](/overview/core-concepts/databases.md#stream) relation in the current `demodb` database and `public` schema:

```sh
demodb.public/demostore# DESCRIBE RELATION "Pageviews";
+----------+---------+-----------+-------------+
|  Name    |  Type   |  Nullable |  Properties |
+==========+=========+===========+=============+
| viewtime | BIGINT  | true      | {}          |
+----------+---------+-----------+-------------+
| userid   | VARCHAR | true      | {}          |
+----------+---------+-----------+-------------+
| pageid   | VARCHAR | true      | {}          |
+----------+---------+-----------+-------------+
```