tp3与tp5获取字段信息的区别

getfield()，value()，column（）区别

代码示例：
tp5:
$lists = Db::name('cangku')->column('name','id');
array(3) {
  [3] => string(6) "昌邑"
  [5] => string(27) "吉林大街（三里屯）"
  [7] => string(12) "测试库房"
}
$lists = Db::name('cangku')->column('name');
array(3) {
  [0] => string(6) "昌邑"
  [1] => string(27) "吉林大街（三里屯）"
  [2] => string(12) "测试库房"
}
$name = M('cangku')->value('name');
string(6) "昌邑";
tp3:
$lists = M('cangku')->getfield('name',true);
array(3) {
  [0] => string(6) "昌邑"
  [1] => string(27) "吉林大街（三里屯）"
  [2] => string(12) "测试库房"
}
$name = M('cangku')->getfield('name');
string(6) "昌邑";