問題描述

我有以下查詢，我嘗試使用 DB::Raw() 進行左連接，但出現錯誤:

I have the following query where I'm trying to use DB::Raw() for the left join but I'm getting error:

IlluminateDatabaseQueryBuilder::leftJoin() 缺少參數 2

Missing argument 2 for IlluminateDatabaseQueryBuilder::leftJoin()

這是我的查詢:

return $this->model->from('alerts as a')
    ->leftJoin(DB::Raw("locations as l on l.id = JSON_UNQUOTE(JSON_EXTRACT(a.criteria, '$.locationId'))"))
    ->leftJoin(DB::Raw("industries as i on find_in_set(i.id, JSON_UNQUOTE(JSON_EXTRACT(a.criteria, '$.industries')))"))
    ->where('user_id', '=', $userId)
    ->selectRaw("a.id
        , a.name
        , a.criteria
        , GROUP_CONCAT(DISTINCT(i.name) SEPARATOR ', ') as 'Industries'
            ->groupBy('a.id')
            ->orderBy('a.created_at', 'desc');

推薦答案

leftJoin 函數聲明如下:

 public function leftJoin($table, $first, $operator = null, $second = null)

您想將原始函數作為第二列傳入:

You want to pass your raw functions in as the second column:

return $this->model->from('alerts as a')
                   ->leftJoin('locations AS l', 'l.id', '=', DB::Raw("JSON_UNQUOTE(JSON_EXTRACT(a.criteria, '$.locationId'))"))
                   ->leftJoin('industries as i', function($join){
                        $join->on(DB::raw("find_in_set(i.id, JSON_UNQUOTE(JSON_EXTRACT(a.criteria,  '$.industries')))",DB::raw(''),DB::raw(''))); 
                   })

                   ->where('user_id', '=', $userId)
                   ->selectRaw("a.id
                             , a.name
                             , a.criteria
                             , GROUP_CONCAT(DISTINCT(i.name) SEPARATOR ', ') as 'Industries'")
                   ->groupBy('a.id')
                   ->orderBy('a.created_at', 'desc');

find_in_set 建議來自這里.

The find_in_set suggestion came from here.

我不確定 '$.locationId' 是什么，但如果它是一個變量，你可以將它作為一個數組中的參數作為 DB 上的第二個參數傳遞::raw() 函數.

I'm not sure what '$.locationId' is, but if it's a variable, you can pass that along as a parameter within an array as the second parameter on the DB::raw() function.

這篇關于Laravel 5.2 - 左加入 DB::Raw 不起作用?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！