問題描述

我的員工和組表之間存在多對多關系.我已經創建了數據透視表，并且一切正常.但是，我的員工表上有一個 sortOrder 列，用于確定它們的顯示順序.sortOrder 列中值為 1 的員工應該排在第一位，值為 2 的員工排在第二位，依此類推.(如果按降序排序，則向后) sortOrder 列是一個允許空值的整數列.

I've got a many to many relationship between my employees and groups table. I've created the pivot table, and all is working correctly with that. However, I've got a sortOrder column on my employees table that I use to determine the order in which they display. Employee with a value of 1 in the sortOrder column should be first, value of 2 should be second, so on. (Or backwards if sorted descending) The sortOrder column is a integer column that allows null values.

我已經設置了我的組模型來按排序列對員工進行排序，但是我遇到了一個問題.始終首先顯示空值.我已經嘗試使用 ISNULL 和類似的 SQL 方法來代替使用的常規asc"或desc"，但我只得到一個錯誤.

I've set up my group model to sort the employees by the sort column, but I've run into a problem. The null values always are displayed first. I've tried using ISNULL and similar SQL methods in place of the regular "asc" or "desc" used, but I only get an error.

這是我的組模型中的代碼:

Here's the code in my Group model:

class Group extends Eloquent {

public function employees()
    {
        return $this->belongsToMany("Employee")->orderBy('sortOrder', 'asc');
    }
}

這是我在控制器中用來訪問我的模型的內容:

And here's what I use in the controller to access my model:

$board = Group::find(6)->employees;

Laravel 中最后對 NULL 值進行排序的技巧是什么?

What's the trick in Laravel to sorting NULL values last?

推薦答案

Laravel 沒有考慮 ISNULL 方法，但是你可以將它作為原始查詢傳入并仍然使用它因為它比 IF 語句更有效，并且如果您的員工人數超過 1000000 人(已接受的答案)，結果將保持不變，如下所示:

Laravel does not take into consideration the ISNULL method however, you can pass it in as a raw query and still make use of it as it's more efficient than IF statements and the results will stay the same if you ever go beyond 1000000 employees (accepted answer), like so:

public function employees()
{
    return $this->hasMany('Employee')
                ->orderBy(DB::raw('ISNULL(sortOrder), sortOrder'), 'ASC');
}

更新:您還可以使用 orderByRaw() 方法:

Update: You can also use the orderByRaw() method:

public function employees()
{
    return $this->hasMany('Employee')
                ->orderByRaw('ISNULL(sortOrder), sortOrder ASC');
}

這篇關于如何在 Laravel 中使用 Eloquent 最后對 NULL 值進行排序的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！