MySQL Show Indexes

The MySQL can use SHOW INDEX statement to display information about the indexes on a particular table. This statement provides valuable information about the indexes defined on the table, such as the index name, column names, index type, and more. This information can be helpful for optimizing your database and understanding the structure of your tables.

The basic syntax of the SHOW INDEX statement is as follows:

SHOW INDEX FROM table_name;

Here’s a breakdown of each part of the statement:

• SHOW INDEX: This is the statement used to retrieve information about the indexes.
• FROM table_name: You specify the name of the table for which you want to see the index information.

Here’s an example of how to use the SHOW INDEX statement in MySQL:

SHOW INDEX FROM employees;

This query will display a result set with information about the indexes defined on the employees table, including the index name, column names, index type (e.g., BTREE for most indexes), unique status, cardinality (an estimate of the number of unique values), and the index comment.

The result set will look something like this:

Table_name | Non_unique | Key_name       | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment
employees  | 0            | PRIMARY          | 1                    | employee_id  | A               | 1000              | NULL         | NULL   |            |          |         
employees  | 1            | idx_last_name | 1                    | last_name      | A               | 1000              | NULL         | NULL   |            |          |        
employees  | 1            | idx_department | 1             | department   | A               | 50                   | NULL         | NULL   |            |          |        

This information can be useful when analyzing the structure of your tables, optimizing query performance, and ensuring the appropriate indexes are in place.