[Solved] Improve Mysql query performance (index in type using explain)

How to optimize this SQL query?

In case you have your own slow SQL query, you can optimize it automatically here.

For the query above, the following recommendations will be helpful as part of the SQL tuning process.
You'll find 3 sections below:

  1. Description of the steps you can take to speed up the query.
  2. The optimal indexes for this query, which you can copy and create in your database.
  3. An automatically re-written query you can copy and execute in your database.
The optimization process and recommendations:
  1. Avoid LIKE Searches With Leading Wildcard (query line: 15): The database will not use an index when using like searches with a leading wildcard (e.g. '%dog%'). Although it's not always a satisfactory solution, please consider using prefix-match LIKE patterns (e.g. 'TERM%').
  2. Create Optimal Indexes (modified query below): The recommended indexes are an integral part of this optimization effort and should be created before testing the execution duration of the optimized query.
  3. Prefer Inner Join Over Left Join (modified query below): We identified that one or more left joined entities (e.g. `images`) are used in the 'where' clause, in a way that allows to replace it with an optimized inner join. Inner joins can be fully optimized by the database, while Left joins apply limitations on the database's optimizer.
Optimal indexes for this query:
ALTER TABLE `galleries` ADD INDEX `galleries_idx_id` (`id`);
ALTER TABLE `users` ADD INDEX `users_idx_id` (`id`);
The optimized query:
        `homestead`.`users` AS users 
        `homestead`.`galleries` AS gal 
            ON users.id = gal.user_id 
        `homestead`.`images` AS img 
            ON img.gallery_id = gal.id 
        img.description LIKE '%dog%'

Related Articles

* original question posted on StackOverflow here.