SHOW INDEX - PolarDB - Alibaba Cloud Documentation Center

You can use the SHOW INDEX statement to view information about the local indexes, global indexes, and columnar indexes on a PolarDB-X table.

Syntax

SHOW {INDEX | INDEXES | KEYS}
    {FROM | IN} tbl_name
    [{FROM | IN} db_name]
    [WHERE expr]

Example

SHOW INDEX FROM t_order;
+--------------+------------+-----------+--------------+----------------+-----------+-------------+----------+--------+------+------------+----------+---------------+
| TABLE   | NON_UNIQUE | KEY_NAME  | SEQ_IN_INDEX | COLUMN_NAME    | COLLATION | CARDINALITY | SUB_PART | PACKED | NULL | INDEX_TYPE | COMMENT  | INDEX_COMMENT |
+--------------+------------+-----------+--------------+----------------+-----------+-------------+----------+--------+------+------------+----------+---------------+
| t_order |          0 | PRIMARY   |            1 | id             | A         |           0 |     NULL | NULL   |      | BTREE      |          |               |
| t_order |          1 | l_i_order |            1 | order_id       | A         |           0 |     NULL | NULL   | YES  | BTREE      |          |               |
| t_order |          0 | g_i_buyer |            1 | buyer_id       | NULL      |           0 |     NULL | NULL   | YES  | GLOBAL     | INDEX    |               |
| t_order |          1 | g_i_buyer |            2 | id             | NULL      |           0 |     NULL | NULL   |      | GLOBAL     | COVERING |               |
| t_order |          1 | g_i_buyer |            3 | order_id       | NULL      |           0 |     NULL | NULL   | YES  | GLOBAL     | COVERING |               |
| t_order |          1 | g_i_buyer |            4 | order_snapshot | NULL      |           0 |     NULL | NULL   | YES  | GLOBAL     | COVERING |               |
+--------------+------------+-----------+--------------+----------------+-----------+-------------+----------+--------+------+------------+----------+---------------+
6 rows in set (0.01 sec)

Table 1. Column descriptions
Column name	Description
TABLE	The name of the table.
NON_UNIQUE	Indicates whether the global secondary index has a unique constraint. Valid values: 1: regular global secondary index; 0: global secondary index with a unique constraint.
KEY_NAME	The name of the index.
SEQ_IN_INDEX	The ordinal number of the index column within the index, starting from 1.
COLUMN_NAME	The name of the index column.
COLLATION	The sorting method. Valid values: A: ascending order; D: descending order; NULL: not sorted.
CARDINALITY	The estimated number of unique values.
SUB_PART	The index prefix. A NULL value indicates that the prefix is the entire column.
PACKED	Information about how the field is compressed. A NULL value indicates no compression.
NULL	Indicates whether null values are allowed.
INDEX_TYPE	The index type. Valid values: NULL (not specified); BTREE; HASH;
COMMENT	Information about the index. Valid values: NULL: The index is a local index. INDEX: The column is an index column of a global secondary index. COVERING: The column is a covering column of a global secondary index.
INDEX_COMMENT	Other information.