Question

这是我的代码

  $query = "select ((recipients.maennlichDeutsch+recipients.maennlichAuslaender+recipients.weiblichDeutsch+recipients.weiblichAuslaender)/inhab.Einwohner) as Sozialhilfeempfaenger,jahr from recipients left join education on recipients.Bundesland = education.FK_Land and recipients.Jahr = education.FK_Jahr left join inhab on recipients.Bundesland = inhab.FK_land and recipients.Jahr = inhab.FK_Jahr where education.Abschluss in ('Hauptschulabschluss') and recipients.Bundesland = '.$_REQUEST['land'].'";
$result=mysqli_query($db, $query) or die('Error querying database.');

$q = "select ((education.weiblich+education.maennlich)/inhab.Einwohner) as 'niedriger Bildungsstand',Jahr from recipients left join education on recipients.Bundesland = education.FK_Land and recipients.Jahr = education.FK_Jahr left join inhab on recipients.Bundesland = inhab.FK_land and recipients.Jahr = inhab.FK_Jahr WHERE education.Abschluss in ('Ohne Haupschulabschluss','Hauptschulabschluss') and recipients.Bundesland = '.$_REQUEST['land'].'";
$r=mysqli_query($db, $q) or die('Error querying database.');

$_REQUEST['land']。我试图获取下拉菜单的选定值。变量土地正在工作，我可以毫无问题地回应它。没有$_REQUEST['land']，查询也可以正常工作。

但现在我得到500错误。你知道我在这里做错了什么吗？

Answer 1

你应该转义你的变量以用双引号连接（因为你用双引号开始你的字符串），改变这个：

$q = "... and recipients.Bundesland = '.$_REQUEST['land'].'";

对此：

$q = "... and recipients.Bundesland = '".$_REQUEST['land']."'";

第一个查询相同。希望它有所帮助。

Answer 2

我认为可能问题出在您的查询行中，您使用双引号打开，然后以单引号结束

 $query = "select.... '.$_REQUEST['land'].'";

尝试使用这个：

 $query = "select.... ".$_REQUEST['land'];

Answer 3

试一试：

$query = "select ((recipients.maennlichDeutsch+recipients.maennlichAuslaender+recipients.weiblichDeutsch+recipients.weiblichAuslaender)/inhab.Einwohner) as Sozialhilfeempfaenger,jahr from recipients left join education on recipients.Bundesland = education.FK_Land and recipients.Jahr = education.FK_Jahr left join inhab on recipients.Bundesland = inhab.FK_land and recipients.Jahr = inhab.FK_Jahr where education.Abschluss in ('Hauptschulabschluss') and recipients.Bundesland = '".$_REQUEST['land']."'";
$result=mysqli_query($db, $query) or die('Error querying database.');

$q = "select ((education.weiblich+education.maennlich)/inhab.Einwohner) as 'niedriger Bildungsstand',Jahr from recipients left join education on recipients.Bundesland = education.FK_Land and recipients.Jahr = education.FK_Jahr left join inhab on recipients.Bundesland = inhab.FK_land and recipients.Jahr = inhab.FK_Jahr WHERE education.Abschluss in ('Ohne Haupschulabschluss','Hauptschulabschluss') and recipients.Bundesland = '".$_REQUEST['land']."'";
$r=mysqli_query($db, $q) or die('Error querying database.');

我认为它有效。 :)，我只是替换＆＃39;为＆＃34;在查询中

Answer 4

连接问题，总是更喜欢使用Curly Brackets来避免这些问题：

Curly Brackets {} Curly括号用于标记类，函数（OOP术语中的方法），循环和控制结构体。

它们也可以在字符串中用于将变量与周围文本分开。

1。 $ verb =＆＃39;添加＆＃39 ;; 2。 echo＆＃34;这个动词的现在时是$ verb＆＃34 ;; 认为你想要显示动词的过去时而不重新定义它（只需添加'ed'）。

1。回声＆＃34;这个动词的过去时是$ verbed＆＃34 ;; 如果您尝试上述方法，那么PHP将搜索变量$ verbed并抛出错误（因为它未定义）。要将动词与后缀“ed”分开，可以使用如下的花括号。

1。 echo＆＃34;这个动词的过去时是{$ verb} ed＆＃34 ;; 如果$ verb是一个数组，则可以使用它的一个元素，如下所示。

1。回声＆＃34;这个动词的过去时是{$ verb [＆＃39; past_tense＆＃39;]}＆＃34 ;; 如果$ verb是一个对象，并且有一个名为getPastTense（）的方法，它返回动词的过去时态，可以像下面一样使用它。

1。 echo＆＃34;这个动词的过去时是{$ verb-＆gt; getPastTense（）}＆＃34;;

 $query = "select ((recipients.maennlichDeutsch+recipients.maennlichAuslaender+recipients.weiblichDeutsch+recipients.weiblichAuslaender)/inhab.Einwohner) as Sozialhilfeempfaenger,jahr from recipients left join education on recipients.Bundesland = education.FK_Land and recipients.Jahr = education.FK_Jahr left join inhab on recipients.Bundesland = inhab.FK_land and recipients.Jahr = inhab.FK_Jahr where education.Abschluss in ('Hauptschulabschluss') and recipients.Bundesland = '{$_REQUEST['land']}'";
$result=mysqli_query($db, $query) or die('Error querying database.');

$q = "select ((education.weiblich+education.maennlich)/inhab.Einwohner) as 'niedriger Bildungsstand',Jahr from recipients left join education on recipients.Bundesland = education.FK_Land and recipients.Jahr = education.FK_Jahr left join inhab on recipients.Bundesland = inhab.FK_land and recipients.Jahr = inhab.FK_Jahr WHERE education.Abschluss in ('Ohne Haupschulabschluss','Hauptschulabschluss') and recipients.Bundesland = '{$_REQUEST['land']}'";
$r=mysqli_query($db, $q) or die('Error querying database.');

Curly Braces Notation in PHP

Answer 5

您可以双引号并在双引号内使用{$ var}。使其更具可读性。

$query = "... and recipients.Bundesland = '{$_REQUEST['land']}'";

我还建议您尝试使用PDO或NotORM。至少通过消毒它来获取你的GET / POST / REQUEST。

基于php变量的mysql查询

5 个答案: