我在找主题。教师可以添加多个主题，学生可以搜索这些主题，并对结果数据进行筛选。学生可以按级别、课程、地点进行筛选。
我的问题是，如果学生没有应用位置过滤器怎么办？
我在过滤器中传递位置字符串，一切对我来说都很好。。但当我不应用位置过滤器时。。它没有为文本查询指定文本。
我的问题是：

$client = ClientBuilder::create()->build();
$location = $request->location;
$level = $request->level;
$curriculum = $request->curriculum;
$params = [
    'index' => 'tutors',
    'body'  => 
    [
        "query" => [
            "bool" => [
                "must" => [
                    [ "term" => [ "approved" => 1 ]],
                    [ "match" => [ "country_en_name" =>  $location ]],
                    [ "match" => [ "local_rates.levels" =>  $level ]],
                    [ "match" => [ "local_rates.curriculums" =>  $curriculum ]],
                ]
            ],
        ]
    ]
];
$search = $client->search($params);

对于null或空值，我也尝试过这样的方法

$client = ClientBuilder::create()->build();
$location = $request->location;
$level = $request->level;
$curriculum = $request->curriculum;
$params = [
    'index' => 'tutors',
    'body'  => 
    [
        "query" => [
            "bool" => [
                "must" => [
                    [ "term" => [ "approved" => 1 ]],
                    $location && $location != null ? [ "match" => [ "country_en_name" =>  $location ]] : '',
                    $level && $level != null ? [ "match" => [ "local_rates.levels" =>  $level ]] : '',
                    $curriculum && $curriculum != null ? [ "match" => [ "local_rates.curriculums" =>  $curriculum ]] : '',
                ]
            ],
        ]
    ]
];
$search = $client->search($params);

但没用，有人能帮我吗？