mysql>SHOW INDEX FROM table_name; +------------+------------+-------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+ | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment | +------------+------------+-------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+ | table_name | 0 | PRIMARY | 1 | id | A | 1000000 | NULL | NULL | | BTREE | | | | table_name | 0 | unique_index_name | 1 | unique_col1 | A | 1000000 | NULL | NULL | | BTREE | | | | table_name | 0 | unique_index_name | 2 | unique_col2 | A | 1000000 | NULL | NULL | | BTREE | | | +------------+------------+-------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
在MySQL中,系统表information_schema中的STATISTICS表记录了所有表的索引信息。通过SHOW INDEX命令可以查询到表的索引信息,其中Index_name字段即代表索引的名称。如果有多个Unique索引,那么他们的名字是不同的,各自存储在系统表中。
综上所述,MySQL中的Unique索引是存储在系统表information_schema.STATISTICS表中的,可以通过SHOW INDEX FROM命令查询得到。