Difference between SHOW INDEX, SHOW INDEXES and SHOW KEYS in MySQL?

There is no difference between show index, show indexes and show keys. They have similar meaning.

Let us first create a table −

mysql> create table DemoTable1549
   -> (
   -> EmployeeId int NOT NULL AUTO_INCREMENT PRIMARY KEY,
   -> EmployeeName varchar(20)
   -> );
Query OK, 0 rows affected (0.82 sec)

Following is the query to create an index −

mysql> create index name_index1 on DemoTable1549(EmployeeName);
Query OK, 0 rows affected (0.41 sec)
Records: 0  Duplicates: 0  Warnings: 0

Following is the query for SHOW INDEX −

mysql> show index from DemoTable1549;

This will produce the following output −

+---------------+------------+-------------+--------------+--------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+
| Table         | Non_unique | Key_name    | Seq_in_index | Column_name  | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment | Visible |
+---------------+------------+-------------+--------------+--------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+
| demotable1549 |          0 | PRIMARY     |            1 | EmployeeId   |         A |           0 |     NULL |   NULL |      | BTREE      |         |               |     YES |
| demotable1549 |          1 | name_index1 |            1 | EmployeeName |         A |           0 |     NULL |   NULL |  YES | BTREE      |         |               |     YES |
+---------------+------------+-------------+--------------+--------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+
2 rows in set (0.17 sec)

Here is the query for SHOW INDEXES −

mysql> show indexes from DemoTable1549;

This will produce the following output −

+---------------+------------+-------------+--------------+--------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+
| Table         | Non_unique | Key_name    | Seq_in_index | Column_name  | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment | Visible |
+---------------+------------+-------------+--------------+--------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+
| demotable1549 |          0 | PRIMARY     |            1 | EmployeeId   |         A |           0 |     NULL |   NULL |      | BTREE      |         |               |     YES |
| demotable1549 |          1 | name_index1 |            1 | EmployeeName |         A |           0 |     NULL |   NULL | YES  | BTREE      |         |               |     YES |
+---------------+------------+-------------+--------------+--------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+
2 rows in set (0.00 sec)

Here is the query to implement SHOW KEYS −

mysql> show keys from DemoTable1549;

This will produce the following output −

+---------------+------------+-------------+--------------+--------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+
| Table         | Non_unique | Key_name    | Seq_in_index | Column_name  | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment | Visible |
+---------------+------------+-------------+--------------+--------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+
| demotable1549 |          0 | PRIMARY     |            1 | EmployeeId   |         A |           0 |     NULL | NULL   |      | BTREE      |         |               |     YES |
| demotable1549 |          1 | name_index1 |            1 | EmployeeName |         A |           0 |     NULL | NULL   | YES  | BTREE      |         |               |     YES |
+---------------+------------+-------------+--------------+--------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+
2 rows in set (0.00 sec)