CURD

public function select(){
        //查询一条
        // $res=User::find(1);
        // $res=User::where('id',1)->first();
        //查询单条数据的单个字段的值
        // $res=User::where('id',1)->value('username');
        //查询单列
        // $res=User::pluck('username','id');

        //查询多条
        // $res=User::all();
        // $res=User::get();
        //查询执行的sql语句
        DB::enableQueryLog();
        //条件查询
        $res=User::from('user as u')    //添加别名
            ->leftJoin('user_token as t','t.user_id','=','u.id')
            ->select('id','username')   //查询部分字段
            ->orderBy('u.id','desc')
            ->orderBy('u.createtime')
            ->get();
        //查询结果追加新字段
        $res->map(function ($item){
            $item['a']=$item['id'];
            return $item;
        });
        $sql=Db::getQueryLog();
        return success(compact('res','sql'));
    }
    public function add(){
        $data['username']='user1';
        $data['nickname']='nickname1';
        $res=User::insert($data);
        // $res=User::insertGetId($data);
        if($res!==false){
            return success($res);
        }else{
            return error();
        }
    }
    public function edit(){
        $data['username']='user2';
        $data['nickname']='nickname1';
        $res=User::where('id',5)->update($data);
        if($res!==false){
            return success($res);
        }else{
            return error();
        }
    }
    public function del(){
        // $res=User::destroy(4);
        $res=User::destroy([3,4]);
        if($res!==false){
            return success($res);
        }else{
            return error();
        }
    }