ClickHouse/docs/en/sql-reference/statements/describe-table.md

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---
toc_priority: 42
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toc_title: DESCRIBE
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---
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# DESCRIBE TABLE {#misc-describe-table}
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Returns information about table columns.
**Syntax**
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``` sql
DESC|DESCRIBE TABLE [db.]table [INTO OUTFILE filename] [FORMAT format]
```
The `DESCRIBE` statement returns a row for each table column with the following [String](../../sql-reference/data-types/string.md) values:
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- `name` — A column name.
- `type` — A column type.
- `default_type` — A clause that is used in the column [default expression](../../sql-reference/statements/create/table.md#create-default-values): `DEFAULT`, `MATERIALIZED` or `ALIAS`. If there is no default expression, then empty string is returned.
- `default_expression` — An expression specified after the `DEFAULT` clause.
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- `comment` — A [column comment](../../sql-reference/statements/alter/column.md#alter_comment-column).
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- `codec_expression` — A [codec](../../sql-reference/statements/create/table.md#codecs) that is applied to the column.
- `ttl_expression` — A [TTL](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-ttl) expression.
- `is_subcolumn` — A flag that equals `1` for internal subcolumns. It is included into the result only if subcolumn description is enabled by the [describe_include_subcolumns](../../operations/settings/settings.md#describe_include_subcolumns) setting.
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All columns in [Nested](../../sql-reference/data-types/nested-data-structures/nested.md) data structures are described separately. The name of each column is prefixed with a parent column name and a dot.
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To show internal subcolumns of other data types, use the [describe_include_subcolumns](../../operations/settings/settings.md#describe_include_subcolumns) setting.
**Example**
Query:
``` sql
CREATE TABLE describe_example (
id UInt64, text String DEFAULT 'unknown' CODEC(ZSTD),
user Tuple (name String, age UInt8)
) ENGINE = MergeTree() ORDER BY id;
DESCRIBE TABLE describe_example;
DESCRIBE TABLE describe_example SETTINGS describe_include_subcolumns=1;
```
Result:
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``` text
┌─name─┬─type──────────────────────────┬─default_type─┬─default_expression─┬─comment─┬─codec_expression─┬─ttl_expression─┐
│ id │ UInt64 │ │ │ │ │ │
│ text │ String │ DEFAULT │ 'unknown' │ │ ZSTD(1) │ │
│ user │ Tuple(name String, age UInt8) │ │ │ │ │ │
└──────┴───────────────────────────────┴──────────────┴────────────────────┴─────────┴──────────────────┴────────────────┘
```
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The second query additionally shows subcolumns:
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``` text
┌─name──────┬─type──────────────────────────┬─default_type─┬─default_expression─┬─comment─┬─codec_expression─┬─ttl_expression─┬─is_subcolumn─┐
│ id │ UInt64 │ │ │ │ │ │ 0 │
│ text │ String │ DEFAULT │ 'unknown' │ │ ZSTD(1) │ │ 0 │
│ user │ Tuple(name String, age UInt8) │ │ │ │ │ │ 0 │
│ user.name │ String │ │ │ │ │ │ 1 │
│ user.age │ UInt8 │ │ │ │ │ │ 1 │
└───────────┴───────────────────────────────┴──────────────┴────────────────────┴─────────┴──────────────────┴────────────────┴──────────────┘
```
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**See Also**
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- [describe_include_subcolumns](../../operations/settings/settings.md#describe_include_subcolumns) setting.