问题

Note: this is laravel 5.3

Basically I'm running a query when a user selects arabic translation.. the full sql looks like this

select s.ref, t.text as ref_ar 
  FROM stores AS s 
  INNER JOIN 
     (SELECT item, text 
      FROM translator_translations 
      WHERE locale ='ar' 
        AND namespace ='*' 
        AND item like 'store.ref%'
      ) AS t 
   ON substring(s.ref_translation from 14 for 26) = t.item;

don't see much documentation on subqueries on the official Laravel docs (there are inner join stuff but not good enough) and the SO advice seems extra-hacky.. advice?

context

this will be used as a scope inside a model, so this works for example:

public function scopeFilterLanguage($query, $language_id)
{
    if (!$language_id || intval($language_id) != LanguageConstants::ARABIC_LANGUAGE_ID) {
        return $query;
    }
    return $query->whereRaw("
    substring(ref_translation from 14 for 26) in 
                                    (select item 
                                     from 
                                     translator_translations 
                                     where 
                                     locale ='ar' and namespace ='*' 
                                     and 
                                     item like 'store.ref%')");

}

but it doesn't give me what i want. (ie i have to use the bigger version at the start of this post)

回答1:

this worked (ignore the dynamic stuff like this->getClassName etc).. the basic logic works just fine

public function scopeAddTranslations($query)
{
    $t = new Translation();

    $subq = $t->select('item','text as ref_ar')
              ->where('locale','=','ar')
              ->where('item','like',$this->getClassName().'.ref%');

    $query->leftjoin(\DB::raw('('.$subq->toSql().') as t'), 
      function ($join) use ($subq) { 
          $join->on(\DB::raw('SUBSTRING('.$this->getTable().'.ref_translation 
                              FROM 14 FOR 26)'),
                                 '=',
                                 \DB::raw('t.item'))
                   ->addBinding($subq->getBindings());
            });
    return $query;
}

回答2:

Here's my completely untested and best guess effort.

public function scopeFilterLanguage($query, $language_id)
{
    if (!$language_id || intval($language_id) != LanguageConstants::ARABIC_LANGUAGE_ID) {
        return $query;
    }
    return $query->join('translator_translations', function($join) {
        $join->selectSub(function($q) {
               $q->where('t.locale' => 'ar')
               $q->where('t.namespace', '*')
               $q->where('t.item', 'like', $this->ref . '%')
          }, 't');
     })->on('t.item', '=', substr($this->ref_translation, 14, 26))
       ->select('t.text', 'ref');
}

来源：https://stackoverflow.com/questions/48747008/how-to-use-inner-joins-with-subqueries-in-laravel-eloquent

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