Laravel MySQL how to order results in the same order as in whereIn clause

问题

I have two queries, the first one gives me an array of ids, that is in a specific order. Then that array of ids I pass it to the second query like so:

 Operation::whereIn('id', $ids)->get();

But when I output the result of that query, the order has changed, if the array $ids was something like (4,2,6,9) which is the order I wanted the results to be in, the output will give me 2,4,6,9. How can I avoid that?

回答1:

MySQL way of sorting with order same as in where in clause:

$ids; // array of ids
$placeholders = implode(',',array_fill(0, count($ids), '?')); // string for the query

Operation::whereIn('id', $ids)
   ->orderByRaw("field(id,{$placeholders})", $ids)->get();

回答2:

You can do

$idsImploded = implode(',',$ids);
Operation::whereIn('id', $ids)->orderByRaw("FIND_IN_SET('id','$idsImploded')")->get();

It's a problem where MySql doesn't return the result in the order you specify them, so you need to reorder them after that.

A similar solution can be found here: avoid Sorting by the MYSQL IN Keyword

回答3:

If you have the sorting order in 4,2,6,9, you can fetch these rows, then use php to sort.

来源：https://stackoverflow.com/questions/26176245/laravel-mysql-how-to-order-results-in-the-same-order-as-in-wherein-clause