[英]how to paginate after a sort by in laravel
I have a Food model.我有一个食物模型。 Each food has a price and a discount (in percent).
每种食物都有价格和折扣(百分比)。 I have appended a cost attribute to hold a value which is calculated base on the first price and discount.
我附加了一个成本属性来保存一个基于第一个价格和折扣计算的值。
Example :示例:
We have a Food with a price of 10$.我们有一个价格为 10 美元的食物。 discount is 10%, so the cost is 9$.
折扣是 10%,所以成本是 9 美元。
class Food extends Model
{
protected $appends = ['cost'];
public function getCostAttribute()
{
return $this->price - round( ($this->price*$this->discount) / 100 );
}
}
I need to order my foods based on cost.我需要根据成本订购我的食物。 I cannot use
orderBy
because cost is not actually a column.我不能使用
orderBy
因为 cost 实际上不是一列。 so I have to use sortBy
.所以我必须使用
sortBy
。
$foods = Food::all();
$foods = $foods->sortBy(function($food){
return $food->cost;
});
Now, how can I paginate $foods
variable?现在,如何对
$foods
变量进行分页? Because I cannot execute following code to paginate因为我无法执行以下代码进行分页
$foods = $foods->paginate(12);
sort by
has already take datas from db, so use pagination is not really helpful. sort by
已经从 db 获取数据,所以使用分页并不是很有帮助。
So I recommend to change your code like this, this will reduce IO cost:所以我建议像这样改变你的代码,这将减少 IO 成本:
Food::select('*',
DB::raw('(price - round((price * discount) / 100)) AS cost')
)->orderBy('cost')
->paginate(12)
You have to use join to sort your item base on the relationship model.您必须使用 join 根据关系模型对项目进行排序。 Try this
尝试这个
$order = 'desc';
$users = Food::join('costs', 'foods.id', '=', 'costs.id')->orderBy('costs.id',
$order)->select('foods.*')->paginate(10);
reference : [ https://laracasts.com/discuss/channels/eloquent/order-by-on-relationship][1]参考:[ https://laracasts.com/discuss/channels/eloquent/order-by-on-relationship][1]
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