解决方法（不想扩展Builder和JoinClause类）：

注意：这将使 - > 所以注意其中在下面被分开。

  $ query = DB :: table（'awards'）
  - > leftJoin（'winners'，function（$ join）
 {
 $ join-> on（'awards.id ， '='， 'winners.award_id'）; 
 $ join-> on（'winners.year'，'='，DB :: raw（'？'））; 
} 
  - > setBindings（array_merge（$ query-> getBindings（），array（$ year）））; 

 $ query-> where（'awards.type'，'color'）; 

 $ awards = $ query-> get（）; 
 

更新： Taylor添加 joinWhere ， leftJoinWhere ...他说如果你有一个函数加入，只需使用 - >其中和 - >或者从关闭之内。我还没有尝试这个。

Let's say I want to show a full list of awards with type="color":

Awards        Type     2013 Winner
======        ====     ===========
Blue Award    color       Tom
Red Award     color
Green Award   color       Dan  

To achieve this result I could have a query in Laravel like this:

$year = '2013';

$awards = DB::table('awards')
             ->leftJoin('winners', function($join) use ($year)
                   {
                        $join->on('awards.id','=','winners.award_id');
                        $join->on('winners.year','=',DB::raw("'".$year."'"));
                   }
             ->where('awards.type','color')
             ->get();

If you output the SQL that Laravel generates you will see that only the WHERE clause is parameterized and $year in the ON clause is left vulnerable to sql injection if I get it from an untrusted source. Also the query's caching potential is reduced because $year will change often. Note: In case you were thinking that I just add the second left join condition to the WHERE of the query, these are not the same.

Any ideas on how to get the $year part of the query parameterized?

Here's an odd work-around (didn't want to extend the Builder and JoinClause classes):
Notice: This will break query chaining with -> so notice the where was seperated below.

$query = DB::table('awards')
         ->leftJoin('winners', function($join)
               {
                    $join->on('awards.id','=','winners.award_id');
                    $join->on('winners.year','=',DB::raw('?'));  
               }
         ->setBindings(array_merge($query->getBindings(),array($year)));

$query->where('awards.type','color');

$awards = $query->get();

UPDATE: Taylor added joinWhere, leftJoinWhere... he says that "if you have a function join just use ->where and ->orWhere from within the Closure." I've yet to try this though.