Laravel Carbon Group 按月
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Laravel Carbon Group by Month
提问by Dev.Wol
Can anyone see what I'm doing wrong?
谁能看到我做错了什么？
I'm trying to output all the months but group them so they are unique.
我试图输出所有月份，但将它们分组以便它们是唯一的。
$months = NewsItem::select(DB::raw('MONTH("created_at") as month'))->groupBy('month')->get();
return $months;
I'm getting the following back
我要回以下内容
{"month":null}
In my database I have five news articles all created_at 05/01/2017 so it's right that I only get one response but I'm not getting the number of the month back?
在我的数据库中，我有五篇新闻文章都是在 2017 年 5 月 1 日创建的，所以我只得到一个回复是对的，但我没有得到当月的数字？
回答by Alexey Mezenin
You can use groupBy()method with closure:
您可以使用groupBy()带闭包的方法：
$months = NewsItem::groupBy(function($d) {
return Carbon::parse($d->created_at)->format('m');
})->get();
Or get data first and then use groupBy()on the Eloquent collection:
或者先获取数据，然后groupBy()在 Eloquent 集合上使用：
$months = NewsItem::get()->groupBy(function($d) {
return Carbon::parse($d->created_at)->format('m');
});
回答by Robert
Why do you need the group by clause in your usecase?
为什么在用例中需要 group by 子句？
You are not fetching any additional data for which a group by is required, you just want to have a list of distinct months, so use distinct.
您不会获取需要 group by 的任何其他数据，您只想获得不同月份的列表，因此请使用 distinct。
$months = NewsItem::selectRaw("MONTH(created_at) as month")->distinct()->get();
Also looking at the solution provided by Alexey, you'll need to fetch the entire dataset from the DB, which is highly inefficient looking at what you are trying to do. A distinct()query would be much faster than a select *and group the results in PHP.
还要查看 Alexey 提供的解决方案，您需要从数据库中获取整个数据集，这在查看您要执行的操作时效率非常低。一个distinct()查询会比更快select *和组的结果PHP。
Edit:
编辑：
Little sidenote here, the reason you get nullreturned as value is because you use a string in the MONTH()function instead of the actual field.
这里有一点旁注，您null作为值返回的原因是因为您在MONTH()函数中使用了字符串而不是实际字段。
回答by Dayachand Patel
You can simply using groupby and mysql MONTH.
您可以简单地使用 groupby 和 mysql MONTH。
$months = NewsItem::groupby(\DB::raw('MONTH(created_at) as month'))->get();
回答by shamaseen
You can do it this way:
你可以这样做：
NewsItem::get(["*",\DB::raw('MONTH(created_at) as month')])->groupBy('month');
