空值被'' [英] Null value is substituted by ''

问题描述

如果$ Time为空，则在查询中它被替换为''。因此查询不正确。如何避免这个问题？

If $Time is null, then in the query it is substituted by ''. As a result the query is incorrect. How to avoid this problem?

$Time = strtotime($arrivals[$i]["time"]);
if ($Time != null)
{
$Time = strftime("%Y-%m-%d %H:%M:%S", $Time);
}

$query="INSERT INTO `Schedule` (`Time`) VALUES('".$Time."');";

结果查询：

INSERT INTO `schedule` (`Time`) VALUES('');

但应该是：

INSERT INTO `schedule` (`Time`) VALUES(null);

推荐答案

如果你想要 NULL ，而不是'2013 -...'，您显然必须多做一点。

If you want NULL in the query instead of '2013-...', you obviously have to do a little more.

if ($Time === null) {
    $Time = 'NULL';
} else {
    $Time = strftime("'%Y-%m-%d %H:%M:%S'", $Time);
    //                ^ note the quotes ^
}

$query = "INSERT INTO `Schedule` (`Time`) VALUES ($Time);";
//                                note: no quotes ^   ^

这篇关于空值被''的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！