Where VS Having?

Question

MySQL

Using Kohana ORM, you can make the following selections:

$session = ORM::factory('User')
    ->with('session')
    ->with('session:status')
    ->where('user_session_status.name', '=', 'active')
    ->find_all();

$session = ORM::factory('User')
    ->with('session')
    ->with('session:status')
    ->having('session:status:name', '=', 'active')
    ->find_all();

The result will be the same, but the second query looks more attractive. The second query won't work with where because:

SELECT user_session_statuses.name AS session:status:name

This is just an example, but there are many more complex queries, and since Having does a post-filtering of the data, I have a question, what are the pitfalls of using having instead of where?

Answer 1

1. Where is faster
2. If you use grouping, then Where will be executed before grouping, and Having after. own having and intended to be used with grouping