SHOW INDEX - MySQL
Overview
SHOW INDEX is a fundamental MySQL command utilized to display detailed information about indices defined on a specific table. It provides valuable insights into index structure, helping users optimize database performance.
Syntax
SHOW INDEX FROM `table_name` [FROM `database_name`]
Required Arguments:
table_name
: The name of the table for which index information is desired.
Optional Arguments:
database_name
: The specific database containing the target table. This argument is omitted when working with the default database.
Options/Flags
None
Examples
Example 1: Display Index Information for a Specific Table
SHOW INDEX FROM my_table;
Example 2: Display Index Information for a Table in a Different Database
SHOW INDEX FROM other_db.my_table;
Common Issues
- Ensure the specified
table_name
exists and you have appropriate access rights. - If no index exists for a table, the command will return an empty result set.
Integration
Combining with EXPLAIN:
To analyze a specific query and understand how indices are being used, combine SHOW INDEX with EXPLAIN:
EXPLAIN SELECT * FROM my_table WHERE id = 10;
SHOW INDEX FROM my_table;
Related Commands
- CREATE INDEX: Creates a new index on a table.
- DROP INDEX: Removes an existing index from a table.
- OPTIMIZE TABLE: Reorganizes a table’s data to improve performance based on index usage.