内容为什么会输出两遍呢？

array(12) {
[0]=>
string(8) "21878959"
["id"]=>
string(8) "21878959"
[1]=>
string(6) "李白"
["name"]=>
string(6) "李白"
[2]=>
string(2) "18"
["age"]=>
string(2) "18"
[3]=>
string(12) "高三一班"
["class"]=>
string(12) "高三一班"
[4]=>
string(1) "0"
["status"]=>
string(1) "0"
[5]=>
string(19) "2015-10-03 12:08:42"
["create_time"]=>
string(19) "2015-10-03 12:08:42"
}