[5.2] Add whereColumn clause

[acasar]

If we want to compare two columns inside a where clause, we now need to write a raw expression:

User::whereRaw('`first_name` = `last_name`');

But with this PR we can use a new whereColumn method:

User::whereColumn('first_name', 'last_name');

As with normal where clauses, array conditions can be passed as well:

User::whereColumn([
    ['first_name', 'last_name'],
    ['updated_at', '>', 'created_at']
]);

[vlakoff]

whereColumn doesn't really describe what it does. Maybe something like whereEqualColumns?

[vlakoff]

Ah, but it's not only about egality. So maybe whereCompareColumns? I can't think of a better name…

[acasar]

It's supposed to function like a sentence: "where column first_name equals (to the column) last_name".

[vlakoff]

It's much clearer, once having kept this in mind.

[JosephSilber]

For a regular where you can also pass an array, but there it's an associative array. Having an associative array means you can't specify the operator, but I think that's fair; if you need different operators, call the method multiple times.

Whatever we do, it should be consistent between these two methods.

[acasar]

A while ago a regular where was updated to allow for the syntax I mentioned above. Since whereColumn is using the same array parsing logic as the normal where, it's entirely consistant.

[JosephSilber]

Oh you're right. Didn't know about that.

Learn something new every day 💯