如何查看我在 MySQL 中设置的索引?
mysqlmysqli database
要查看索引，您可以使用 SHOW 命令。
以下是语法 −
show index from yourTableName;
首先我们创建一个表 −
mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, FirstName varchar(20), LastName varchar(20) ); Query OK, 0 rows affected (0.46 sec)
以下是创建索引的查询 −
mysql> create index id_FirstName on DemoTable(Id,FirstName); Query OK, 0 rows affected (0.52 sec) Records : 0 Duplicates : 0 Warnings : 0
以下是查看我在 MySQL 中设置的索引的查询−
mysql> show index from DemoTable;
这将产生以下输出，同时显示索引 −
+--------------+------------+--------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+ | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment | Visible | +--------------+------------+--------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+ | DemoTable | 0 | PRIMARY | 1 | Id | A | 0 | NULL | NULL | | BTREE | | | YES | | DemoTable | 1 | id_FirstName | 1 | Id | A | 0 | NULL | NULL | | BTREE | | | YES | | DemoTable | 1 | id_FirstName | 2 | FirstName | A | 0 | NULL | NULL | YES | BTREE | | | YES | +--------------+------------+--------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+ 3 rows in set (0.26 sec)
