ModelName::where(function ($query) use ($a) {
    $query->where('a', '=', $a)->orWhereNull('a');

})
->where(function ($query) use ($b,$c) {
    $query->where('b', '=', $b)
          ->orWhere('c', '=', $c);
})->where('d',$d);

输出查询:

SELECT * FROM ModelName WHERE (a='a'或a为空)AND (b='b'或 c='c') AND d='d';

在Laravel Eloquent中简单使用:

$a='foo', $b='bar', $c='john', $d='doe';

Coder::where(function ($query) use ($a, $b) {
    $query->where('a', '=', $a)
          ->orWhere('b', '=', $b);
})->where(function ($query) use ($c, $d) {
    $query->where('c', '=', $c)
          ->orWhere('d', '=', $d);
})->get();

将产生如下查询:

SELECT * FROM <table> WHERE (a='foo' or b='bar') AND (c='john' or d='doe');

你可以使用:

Model::where('table_column', 'value')->orWhere('table_column', 'value')->get()

你也可以使用查询作用域来让事情变得更整洁，所以你可以这样做:

Invoice::where('account', 27)->notPaidAt($date)->get();

然后在你的模型中

public function scopeNotPaidAt($query, $asAt)
{
    $query = $query->where(function ($query) use ($asAt) { 
        $query->where('paid', '=', '0000-00-00')->orWhere('paid', '>=', $asAt); 
    });
    return $query;    
}

ModelName::where(function ($query) use ($a) {
    $query->where('a', '=', $a)->orWhereNull('a');

})
->where(function ($query) use ($b,$c) {
    $query->where('b', '=', $b)
          ->orWhere('c', '=', $c);
})->where('d',$d);

输出查询:

SELECT * FROM ModelName WHERE (a='a'或a为空)AND (b='b'或 c='c') AND d='d';

YourModel::where(function ($query) use($a,$b) {
    $query->where('a','=',$a)
          ->orWhere('b','=', $b);
})->where(function ($query) use ($c,$d) {
    $query->where('c','=',$c)
          ->orWhere('d','=',$d);
});