Whats query can be used to get the details of Indexes of any table?
Whats query can be used to get the details of Indexes of any table? I need this to find out prima开发者_StackOverflow社区rykey/autoincremented value of any table.. Please help/Guide me...
You can use
show indexes from your_table;
For more informations : 12.4.5.23. SHOW INDEX Syntax
As a quick demo (on a not-quite-optimized table) :
mysql> show indexes from post;
+-------+------------+-----------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment |
+-------+------------+-----------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| post | 0 | PRIMARY | 1 | id | A | 7 | NULL | NULL | | BTREE | |
| post | 1 | id_blog_idx | 1 | id_blog | A | 2 | NULL | NULL | | BTREE | |
| post | 1 | id_user_idx | 1 | id_user | A | 7 | NULL | NULL | | BTREE | |
| post | 1 | code_syntax_idx | 1 | code_syntax | A | 7 | NULL | NULL | | BTREE | |
| post | 1 | code_status_idx | 1 | code_status | A | 2 | NULL | NULL | | BTREE | |
| post | 1 | id_category_idx | 1 | id_category | A | 7 | NULL | NULL | | BTREE | |
+-------+------------+-----------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
6 rows in set (0,00 sec)
Note, though, that this will display indexes -- and auto_increment
doesn't have much to do with indexes.
If you want to see the auto_increment
of your table, you can use desc
:
desc your_table;
For more informations : 12.8.1. DESCRIBE Syntax
And, for example, with the same table :
mysql> desc post;
+--------------------+------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+--------------------+------------------+------+-----+---------+----------------+
| id | int(10) unsigned | NO | PRI | NULL | auto_increment |
| id_blog | int(10) unsigned | NO | MUL | NULL | |
| id_user | int(10) unsigned | NO | MUL | NULL | |
...
...
| nb_comments | smallint(6) | NO | | 0 | |
+--------------------+------------------+------+-----+---------+----------------+
17 rows in set (0,05 sec)
Also, an alternate way (which also shows you the current value of the AUTO_INCREMENT counter) is:
=> SHOW CREATE TABLE activations;
Yielding
CREATE TABLE `activations` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`user_id` int(11) DEFAULT NULL,
`created_at` datetime DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=104974 DEFAULT CHARSET=utf8
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