DESC[RIBE]
Purpose
Use this statement to print column information for a given table or view.
Prerequisites
- If the object to be described is a table, one of the following conditions must be fulfilled:
- The current user has one of the following system privileges: SELECT ANY TABLE (or SELECT ANY DICTIONARY in context of system tables, respectively), INSERT ANY TABLE, UPDATE ANY TABLE, DELETE ANY TABLE, ALTER ANY TABLE or DROP ANY TABLE.
- The current user has any object privilege on the table.
- The table belongs to the current user or one of his roles.
- If the object to be described is a view, one of the following conditions must be fulfilled:
- The current user has one of the following system privileges: SELECT ANY TABLE or DROP ANY VIEW.
- The current user has any object privilege on the view.
- The view belongs to the current user or one of his roles.
Syntax
describe::=
Usage Notes
- The SQL_TYPE column displays the datatype. In case of a string type, the used character set will be additionally shown (ASCII or UTF-8).
- The NULLABLE column indicates whether the column is permitted to contain NULL values.
- The value of columns DISTRIBUTION_KEY and PARTITION_KEY show whether the column is part of the distribution and partition keys (for additional information, see ALTER TABLE (distribution/partitioning)). For Views these values are always NULL.
- If you specify the option FULL, then the additional column COLUMN_COMMENT displays the column comment (cut to maximum 200 characters), if this was set either implicitly by the CREATE TABLE or CREATE VIEW command or explicitly by the COMMENT statement.
- DESCRIBE can be abbreviated by DESC (for example, DESC my_table;).
Example
CREATE TABLE t (i DECIMAL COMMENT IS 'id column',
d DECIMAL(20,5),
j DATE,
k VARCHAR(5),
DISTRIBUTE BY i,
PARTITION BY d);
DESCRIBE t;
Example Result
COLUMN_NAME | SQL_TYPE | NULLABLE | DISTRIBUTION_KEY | PARTITION_KEY |
---|---|---|---|---|
I | DECIMAL(18,0) | TRUE | TRUE | FALSE |
D | DECIMAL(20,5) | TRUE | FALSE | TRUE |
J | DATE | TRUE | FALSE | FALSE |
K | VARCHAR(5) UTF-8 | TRUE | FALSE | FALSE |