PHP选择多个desc限制？

Question

在我的sql表中，我有超过300000个条目。

 $marketname = more then 200 !

使用此选项我可以看到最后15个条目。

$sql = "SELECT price FROM markets where market = '" . $marketname . "' order by time desc LIMIT 15,1";
$sql = "SELECT price FROM markets where market = '" . $marketname . "' order by time desc LIMIT 15,1";

等等，最后30,60,120。

$sql = "SELECT price FROM markets where market = '" . $marketname . "' order by time desc LIMIT 30,1";
$sql = "SELECT price FROM markets where market = '" . $marketname . "' order by time desc LIMIT 60,1";

但是有没有一个组合，因为当我在一个页面上展示它在200个市场时非常慢!!

喜欢..

$sql = "SELECT price FROM markets where market = '" . $marketname . "' order by time desc LIMIT 15,1 AND LIMIT 30,1 AND LIMIT 60,1 AND LIMIT 120,1";

Answer 1

首先，尽量不要做SQL注入式SQL。将PDO或MySQLi与预准备语句一起使用。考虑到这一点，请不要限制查询的最后部分。

SELECT price FROM markets WHERE market = :marketName ORDER BY time DESC limit 100

将通过marketname（准备声明）查询市场价格，订购并将其限制为100条记录。