> describe users;
+------------+-----------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+------------+-----------------------+------+-----+---------+----------------+
| id | mediumint(8) unsigned | NO | PRI | NULL | auto_increment |
| first_name | varchar(80) | NO | | NULL | |
| last_name | varchar(80) | NO | | NULL | |
| email | varchar(80) | NO | UNI | NULL | |
+------------+-----------------------+------+-----+---------+----------------+
These keys are indexes. To get more details about each of the indexes on this table, we can use the show indexes
command.
> show indexes in users;
+-------+------------+--------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+-------+------------+--------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| users | 0 | PRIMARY | 1 | id | A | 0 | NULL | NULL | | BTREE | | |
| users | 0 | unique_email | 1 | email | A | 0 | NULL | NULL | | BTREE | | |
+-------+------------+--------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+