laravel|laravel left join携带多个条件的写法 laravelleftjoin携带多个条件的写

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【laravel|laravel left join携带多个条件的写法】在laravel中使用leftJoin添加多个条件时，如select a.* from a left join b on a.id = b.pid and b.status = 1这种类似sql，发现框架自身封装的leftJoin不支持多个参数传递（当然可用写原生sql），laravel框架自身封装的leftJoin方法如下：

public function leftJoin($table, $first, $operator = null, $second = null)
{
return $this->join($table, $first, $operator, $second, 'left');
}

浏览下 \vendor\laravel\framework\src\Illuminate\Database\Query\Builder.php文件，发现join方法可用实现自己想要的left join携带多参数。laravel自身的join方法如下：

public function join($table, $one, $operator = null, $two = null, $type = 'inner', $where = false)
{
// If the first "column" of the join is really a Closure instance the developer
// is trying to build a join with a complex "on" clause containing more than
// one condition, so we'll add the join and call a Closure with the query.
if ($one instanceof Closure) {
$join = new JoinClause($type, $table);
call_user_func($one, $join);
$this->joins[] = $join;
$this->addBinding($join->bindings, 'join');
}
// If the column is simply a string, we can assume the join simply has a basic
// "on" clause with a single condition. So we will just build the join with
// this simple join clauses attached to it. There is not a join callback.
else {
$join = new JoinClause($type, $table);
$this->joins[] = $join->on(
$one, $operator, $two, 'and', $where
);
$this->addBinding($join->bindings, 'join');
}
return $this;
}

当左右连接携带多条件时，可以这样写：

DB::table('app_a as a') ->join('app_b as b',function($join){ $join->on('a.id','=','b.goodId') ->where('b.status','=','SUCCESS') ->where('b.type','=','UNLOCK'); }, null,null,'left') ->where('a.id','>',1) ->get(); //相当于 SELECT * FROM app_a as a LEFT JOIN app_b as b on a.id = b.goodId and b.status = 'SUCCESS' and b.type = 'UNLOCK' where a.id > 1;

当join不传left时，默认是inner。
转载于:https://my.oschina.net/u/3403514/blog/1819202