Question

当我将季节结束日期作为变量传递给此函数时，我收到此错误：警告：除零

function win_percentage($season_start, $season_end)
{
    $wins = mysql_query("SELECT COUNT(result) FROM scorecards WHERE result = 'Won' AND gamedate >= $season_start AND gamedate <= $season_end;");
    $losses = mysql_query("SELECT COUNT(result) FROM scorecards WHERE result = 'Lost' AND gamedate >= $season_start AND gamedate <= $season_end;");
    $winstotal = mysql_fetch_array($wins);
    $lossestotal = mysql_fetch_array($losses);
    $resultgames = $winstotal['COUNT(result)'] + $lossestotal['COUNT(result)'];
    $winratio = ROUND(($winstotal['COUNT(result)'] / $resultgames),2) * 100;
    return $winratio;
}
echo win_percentage('2012-01-01', '2012-09-10')

输出：警告：除以零

但是，当我将季节结束的日期值直接放在函数中时，它可以完美地运行。这些代码块之间的唯一区别是第3行和第4行的结束，其他一切都是相同的。为什么我不能在没有抛出错误的情况下将season_end传递给这个函数？

function win_percentage($season_start, $season_end)
{
    $wins = mysql_query("SELECT COUNT(result) FROM scorecards WHERE result = 'Won' AND gamedate >= $season_start AND gamedate <= '2012-12-31';");
    $losses = mysql_query("SELECT COUNT(result) FROM scorecards WHERE result = 'Lost' AND gamedate >= $season_start AND gamedate <= '2012-12-31';");
    $winstotal = mysql_fetch_array($wins);
    $lossestotal = mysql_fetch_array($losses);
    $resultgames = $winstotal['COUNT(result)'] + $lossestotal['COUNT(result)'];
    $winratio = ROUND(($winstotal['COUNT(result)'] / $resultgames),2) * 100;
    return $winratio;
}
echo win_percentage('2012-01-01', '2012-09-10')

输出：57％

提前致谢！

Answer 1

您需要将日期放在引号中：

$wins = mysql_query("SELECT COUNT(result) FROM scorecards WHERE result = 'Won' AND gamedate >= $season_start AND gamedate <= '$season_end';");
$losses = mysql_query("SELECT COUNT(result) FROM scorecards WHERE result = 'Lost' AND gamedate >= $season_start AND gamedate <= '$season_end';");

如果您开始使用mysqli或PDO并使用它们的绑定参数，这种事情会容易得多 - 它会为您处理所有引用，以及避免SQL注入。

Answer 2

在查询中使用{/ 1}}时，您应该在日期值之前和之后加上'：AND gamedate >= '$season_start' AND gamedate <= '$season_end'

您还应该使用mysqli。

您还应避免将日期保留为数据库中的字符串。

将两个日期传递给PHP函数

2 个答案: