![MySQL InnoDB: Primary Key always included in secondary indexes as the right-most columns… or not – lefred blog: tribulations of a MySQL Evangelist MySQL InnoDB: Primary Key always included in secondary indexes as the right-most columns… or not – lefred blog: tribulations of a MySQL Evangelist](https://i0.wp.com/lefred.be/wp-content/uploads/2024/02/05.png?resize=1024%2C510&ssl=1)
MySQL InnoDB: Primary Key always included in secondary indexes as the right-most columns… or not – lefred blog: tribulations of a MySQL Evangelist
![KB-1413 MySQL Best Practices - Primary Key or unique index on every table - Appian Knowledge Base - Support - Appian Community KB-1413 MySQL Best Practices - Primary Key or unique index on every table - Appian Knowledge Base - Support - Appian Community](https://community.appian.com/resized-image/__size/952x386/__key/communityserver-wikis-components-files/00-00-00-00-11/2017_2D00_11_2D00_07_5F00_16_2D00_31_2D00_17.png)
KB-1413 MySQL Best Practices - Primary Key or unique index on every table - Appian Knowledge Base - Support - Appian Community
![indexing - MySQL is not using the primary key that's implicitly appended to this secondary index - Stack Overflow indexing - MySQL is not using the primary key that's implicitly appended to this secondary index - Stack Overflow](https://i.stack.imgur.com/fXRp3.jpg)
indexing - MySQL is not using the primary key that's implicitly appended to this secondary index - Stack Overflow
![MySQL InnoDB: Primary Key always included in secondary indexes as the right-most columns… or not – lefred blog: tribulations of a MySQL Evangelist MySQL InnoDB: Primary Key always included in secondary indexes as the right-most columns… or not – lefred blog: tribulations of a MySQL Evangelist](https://i0.wp.com/lefred.be/wp-content/uploads/2024/02/06.png?resize=948%2C653&ssl=1)
MySQL InnoDB: Primary Key always included in secondary indexes as the right-most columns… or not – lefred blog: tribulations of a MySQL Evangelist
![An in-depth look at Database Indexing | by Kousik Nath | We've moved to freeCodeCamp.org/news | Medium An in-depth look at Database Indexing | by Kousik Nath | We've moved to freeCodeCamp.org/news | Medium](https://miro.medium.com/v2/resize:fit:741/1*UFE8n19lTjwG4jaOcdsORw.png)
An in-depth look at Database Indexing | by Kousik Nath | We've moved to freeCodeCamp.org/news | Medium
![The primary key is the default clustered index in SQL Server and MySQL. This implies a 'clustered index penalty' on all non-clustered indexes. The primary key is the default clustered index in SQL Server and MySQL. This implies a 'clustered index penalty' on all non-clustered indexes.](https://use-the-index-luke.com/static/fig05_03_secondary_index_on_clustered_index.x1.Q21aCRSZ.png)
The primary key is the default clustered index in SQL Server and MySQL. This implies a 'clustered index penalty' on all non-clustered indexes.
![database design - MySQL is there a point to having a primary key on a lookup table which referrers to a primary key on another table which is indexed? - Stack Overflow database design - MySQL is there a point to having a primary key on a lookup table which referrers to a primary key on another table which is indexed? - Stack Overflow](https://i.stack.imgur.com/Bousa.png)