容易产生错误的where条件

错误的方式：
$where = [];
if ($type == 'wait') {
    $where['status'] = 0;
}
if ($type == 'done') {
    $where['status'] = ['exp', '=1 or status = 2'];
}
$where['employee_id'] = $id;

return DB::M()
    ->table(self::TABLE)
    ->where($where)
    ->order('add_time desc')
    ->select();

SQL：
1：SELECT * FROM oa_employee_bill  WHERE  `status`='0' AND `employee_id`='4'  ORDER BY add_time desc [Exec:0.00058984756469727s]
2：SELECT * FROM oa_employee_bill  WHERE  `employee_id`='4'  ORDER BY add_time desc [Exec:0.00065398216247559s]
3：SELECT * FROM oa_employee_bill  WHERE  `status`  =1 or status = 2 AND `employee_id`='4'  ORDER BY add_time desc [Exec:0.00068211555480957s]

WHERE  （`status`  =1 ）or （status = 2 AND `employee_id`='4'） 

正确的方式：

$where = [];
if ($type == 'wait') {
    $where['status'] = 0;
}
if ($type == 'done') {
    $where['status'] = ['exp', '>0 and status < 3'];
}
$where['employee_id'] = $id;

return DB::M()
    ->table(self::TABLE)
    ->where($where)
    ->order('add_time desc')
    ->select();

SQL：
1： SELECT * FROM oa_employee_bill  WHERE  `employee_id`='4'  ORDER BY add_time desc [Exec:0.00057578086853027s]
2： SELECT * FROM oa_employee_bill  WHERE  `status`='0' AND `employee_id`='4'  ORDER BY add_time desc [Exec:0.00056815147399902s]
3： SELECT * FROM oa_employee_bill  WHERE  `status`  >0 and status < 3 AND `employee_id`='4'  ORDER BY add_time desc [Exec:0.00062203407287598s]

 WHERE  `status`  >0 and status < 3 AND `employee_id`='4' 只是一个情况