How to view MySQL Indexes

View the MySQL index. What information is displayed? The following describes how to view MySQL indexes. I hope this will help you learn MySQL indexes.

Mysql> show index from tblname;
Mysql> show keys from tblname;
· Table
Table name.
· Non_unique
If the MySQL index cannot contain duplicate words, the value is 0. If yes, it is 1.
· Key_name
The name of the index.
· Seq_in_index
The column serial number in the index, starting from 1.
· Column_name
Column name.
· Collation
How the column is stored in the index. In MySQL, values 'a' are in ascending order) or NULL is not classified ).
· Cardinality
The estimated number of unique values in the MySQL index. You can update analyze table or myisamchk-a by running analyze table. The base number is counted based on the statistical data stored as an integer. Therefore, this value is not required to be accurate even for small tables. The larger the base, the larger the chance for MySQL to use the index for union.
· Sub_part
If a column is partially indexed, it is the number of indexed characters. If the entire column is indexed, the value is NULL.
· Packed
Indicates how keywords are compressed. If it is not compressed, It is NULL.
· Null
If the column contains NULL, YES is included. If NO, the column contains NO.
· Index_type
Used Index Methods: BTREE, FULLTEXT, HASH, RTREE ).
· Comment

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