DESCRIBE returns the column definition of the table.
Syntax

DESC|DESCRIBE TABLE [db.]table [INTO OUTFILE filename] [FORMAT format]

The DESCRIBE statement returns one row for each table column, containing the following string values:

• name — column name.
• type — column type.
• default_type — the clause used in the column default expression: DEFAULT, MATERIALIZED, or ALIAS. If there is no default expression, then returns an empty string.
• default_expression — the expression specified after the DEFAULT clause.
• comment — column comment.
• codec_expression — the encoding applied to this column.
• ttl_expression — TTL expression.
• is_subcolumn — for internal subcolumns, the value is 1. This flag is only included in the result when subcolumn description is enabled by passing the describe_include_subcolumns setting.

Example

-- create a table 
CREATE TABLE describe_example ( 
    id UInt64, text String DEFAULT 'unknown' CODEC(ZSTD), 
    user Tuple (name String, age UInt8) 
) ENGINE = CnchMergeTree() ORDER BY id; 

-- returns the definition of columns in the table 
DESCRIBE TABLE describe_example; 
┌─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) │              │                    │         │                  │                │ 
└──────┴───────────────────────────────┴──────────────┴────────────────────┴─────────┴──────────────────┴────────────────┘