I am working on a project, i ran a migration and stumbled on an error, here is my code.

Schema::create('tasks', function (Blueprint $table) {
    $table->increments('id');
    $table->string('name');
    $table->integer('project_id')->unsigned();
    $table->integer('user_id')->unsigned();
    $table->integer('days')->unsigned()->nullable();
    $table->integer('hours')->unsigned()->nullable();

    $table->foreign('company_id')->unsigned()->nullable();
    $table->foreign('user_id')->references('id')->on('users');

    $table->foreign('project_id')->references('id')->on('projects');
    $table->foreign('company_id')->references('id')->on('companies');
    $table->timestamps();
});

这是错误 .

Illuminate \ Database \ QueryException：SQLSTATE [42000]：语法错误或访问冲突：1064 SQL语法中有错误;查看与您的MariaDB服务器版本对应的手册，以便在第1行的'）'附近使用正确的语法（SQL：alter table tasks add constraint tasks_company_id_foreign foreign key（company_id）references``（））1 PDOException ::（“SQLSTATE [42000]：语法错误或访问冲突：1064您的SQL语法中有错误;请检查与您的MariaDB服务器版本对应的手册，以便在第1行的“）'附近使用正确的语法”C：\ xampp \ htdocs \ blog \ vendor \ laravel \ framework \ src \ Illuminate \ Database \ Connection.php：452 2 PDO :: prepare（“alter table tasks add constraint tasks_company_id_foreign foreign key（company_id）references”`（）“）C：\ xampp \ htdocs中\博客\供应商\ laravel \框架的\ src \照亮\数据库\ Connection.php：452

我需要一些帮助 .

laravel-5.6