Project: StarRocks (App Definition and Development / Database)
File: DESCRIBE.md

displayed_sidebar: "English" You can use the statement to perform the following operations: View the schema of a table stored in your StarRocks cluster, along with the type of the and of the table. View the schema of a table stored in the following external data sources, such as Apache Hive. Note that you can perform this operation only in StarRocks 2.4 and later versions. ```SQL DESCtable_name [ALL]; ``` | Parameter | Required | Description | | - | | | | catalogname | No | The name of the internal catalog or an external catalog. <ul><li>If you set the value of the parameter to the name of the internal catalog, which is `defaultcatalog`, you can view the schema of the table stored in your StarRocks cluster. </li><li>If you set the value of the parameter to the name of an external catalog, you can view the schema of the table stored in the external data source.</li></ul> | | db_name | No | The database name. | | table_name | Yes | The table name. | | ALL | No | <ul><li>If this keyword is specified, you can view the type of the sort key, materialized view, and schema of a table stored in your StarRocks cluster. If this keyword is not specified, you only view the table schema. </li><li>Do not specify this keyword when you view the schema of a table stored in an external data source.</li></ul> | ```Plain +--++-+++--++-+ | IndexName | IndexKeysType | Field | Type | Null | Key | Default | Extra | +--++-+++--++-+ ``` The following table describes the parameters returned by this statement. | Parameter | Description | | - | | | IndexName | The table name. If you view the schema of a table stored in an external data source, this parameter is not returned. | | IndexKeysType | The type of the sort key of the table. If you view the schema of a table stored in an external data source, this parameter is not returned. | | Field | The column name. | | Type | The data type of the column. | | Null | Whether the column values can be NULL. <ul><li>`yes`: indicates the values can be NULL. </li><li>`no`: indicates the values cannot be NULL. </li></ul>| | Key | Whether the column is used as the sort key. <ul><li>`true`: indicates the column is used as the sort key. </li><li>`false`: indicates the column is not used as the sort key. </li></ul>| | Default | The default value for the data type of the column. If the data type does not have a default value, a NULL is

| | Extra | <ul><li>If you see the schema of a table stored in your StarRocks cluster, this field displays the following information about the column: <ul><li>The aggregate function used by the column, such as `SUM` and `MIN`. </li><li>Whether a bloom filter index is created on the column. If so, the value of `Extra` is `BLOOM_FILTER`. </li></ul></li><li>If you see the schema of a table stored in external data sources, this field displays whether the column is the partition column. If the column is the partition column, the value of `Extra` is `partition key`. </li></ul>| Note: For information about how a materialized view is displayed in the output, see Example 2. Example 1: View the schema of `example_table` stored in your StarRocks cluster. ```SQL DESC example_table; ``` Or ```SQL DESC defaultcatalog.exampledb.example_table; ``` The output of the preceding statements is as follows. ```Plain +-+++-++-+ | Field | Type | Null | Key | Default | Extra | +-+++-++-+ | k1 | TINYINT | Yes | true | NULL | | | k2 | DECIMAL(10,2) | Yes | true | 10.5 | | | k3 | CHAR(10) | Yes | false | NULL | | | v1 | INT | Yes | false | NULL | | +-+++-++-+ ``` Example 2: View the schema, type of the sort key, and materialized view of `salesrecords` stored in your StarRocks cluster. In the following example, one materialized view `storeamt` is created based on `sales_records`. ```Plain DESC db1.sales_records ALL; +++--+--++-++-+ | IndexName | IndexKeysType | Field | Type | Null | Key | Default | Extra | +++--+--++-++-+ | salesrecords | DUPKEYS | record_id | INT | Yes | true | NULL | | | | | seller_id | INT | Yes | true | NULL | | | | | store_id | INT | Yes | true | NULL | | | | | sale_date | DATE | Yes | false | NULL | NONE | | | | sale_amt | BIGINT | Yes | false | NULL | NONE | | | | | | | | | | | storeamt | AGGKEYS | store_id | INT | Yes | true | NULL | | | | | sale_amt | BIGINT | Yes | false | NULL | SUM | +++--+--++-++-+ ``` Example 3: View the schema of `hive_table` stored in your Hive cluster. ```Plain DESC hivecatalog.hivedb.hive_table; +-+-++-+++ | Field | Type | Null | Key | Default | Extra | +-+-++-+++ | id | INT | Yes | false | NULL | | | name | VARCHAR(65533) | Yes | false | NULL | | | date | DATE | Yes | false | NULL | partition key | +-+-++-+++ ```