预处理语句查询函数

<?php
$host = ‘localhost‘;
$user = ‘root‘;
$pass = ‘‘;
$dbname = ‘db‘;
$charset = ‘utf8‘;
$m = new mysqli($host,$user,$pass,$dbname);
$m->set_charset($charset);
//$tn为表明，$f为查询的字段名，不写则为全部，$w为条件，$o为按照顺序排序，$l为显示几条信息
function select($tn,$f=‘*‘,$w=‘1=1‘,$o=‘‘,$l=0){
	global $m;
	if($l<=0){
		$stmt=$m->prepare("select $f from $tn where $w $o");
	}else{
		$stmt=$m->prepare("select $f from $tn where $w $o limit $l");
		}
		$stmt->execute();
		$rows=$stmt->get_result()->fetch_all(2);
		$stmt->free_result();
		$stmt->close();
		return $rows;
	
}

//查询语句函数的使用$tn为表明，$f为查询的字段名，不写则为全部，$w为条件，$o为按照顺序排序，$l为显示几条信息
$re=select(‘stu‘,‘sname,sscore‘,‘sscore>10‘,‘order by sscore asc‘,5 );
echo ‘<pre>‘;
var_dump($re);