请教下，我用的MSSQL2012，执行以下查询
$data = $Form->field('GroupName')->find(1);
或者是
$data = $Form->field('GroupName')->where('id=1')->select();
其实应该相当于是在执行
SELECT GroupName FROM px_group WHERE id = 1

但是我用$Form->getLastSql()得到的语句却是下面这条
SELECT T1.* FROM (SELECT thinkphp.*, ROW_NUMBER() OVER ( ORDER BY rand()) AS ROW_NUMBER FROM (SELECT GroupName FROM px_group WHERE ( id = 1 )) AS thinkphp) AS T1 WHERE (T1.ROW_NUMBER BETWEEN 1 AND 1)

被框架这么一转是不是会影响效率？