控制Eloquent作用域的运行顺序

Question

I have a simple Eloquent scope that I would like to always run after all the other "Where" statements in the final query to optimize the efficiency of the query. I would like it to run last, no matter where I put it in the query builder (it's for a large application where this scope has been used many times, and I'd like it to be fool-proof in the future)

I'll put the scope below, but it's exactly the same as the example in the Eloquent documentation.

    public function scopeActive($query)
    {
        $query->where('active', 1);
    }

I know eloquent is smart enough to put ordering statements after Where statements, so maybe there's a trick to use that logic to manipulate the order of the where statements, but so far I can't see it. I'm using MySQL if there's some kind of raw sql I can run.

Answer 1

SELECT ...
    WHERE foo > 123
      AND active = 1

will [probably] run faster if you have

INDEX(active, foo)

Note that, regardless of where active=1 is in the WHERE clause, putting active _first in the INDEX` is optimal.

My point here is "always run after other Wheres" is not the proper goal to try to achieve. So...

I don't know if Eloquent can 'automatically' add such a statement, but maybe we can achieve the equivalent goal inside MySQL. (There are a hundred frameworks that try to hide MySQL from the user. I cannot learn them all; instead, I try to help users work around the framework deficiencies. The framework user needs to learn both the framework and the underlying database.)

• Create a VIEW on top of the TABLE , where the VIEW : SELECT * FROM tbl WHERE active = 1 . Then tell Eloquent to access that View instead of the underlying Table. (I suspect the framework's syntax is the same.)
• Add active, to the beginning of most of the indexes for the table (Views cannot be indexes.)

If you need to discuss this further (either before or after making such changes), please provide SHOW CREATE TABLE and EXPLAIN SELECT... There could be other issues make my advice not as good as I hope.