[英]Unknown column '' in 'where clause'
My query is throwing up this error.我的查询抛出了这个错误。 Can anyone see why?
谁能明白为什么?
$query = "SELECT * FROM Units WHERE ID = `$uniqueUnits[a]`";
Unknown column '' in 'where clause'
'where子句'中的未知列''
Two problems.两个问题。
You're using backticks to delimit a string.您正在使用反引号来分隔字符串。 Backticks delimit fields , so MySQL thinks you're trying to give it a column name.
反引号分隔字段,因此 MySQL 认为您正在尝试给它一个列名。
The error message indicates that, in fact, this value that it thinks is a column name, is empty.错误消息表明,实际上,它认为是列名的这个值是空的。 So your value
$uniqueUnits[a]
is probably broken, or not being interpolated correctly.因此,您的价值
$uniqueUnits[a]
可能已损坏,或者未正确插值。
You should do the following:您应该执行以下操作:
Interpolate your variables explictly with the "complex syntax" to be sure that the string forms properly;使用“复杂语法”明确地插入变量,以确保字符串 forms 正确;
Check the value of $query
so that you can see what's going on:检查
$query
的值,以便您可以看到发生了什么:
print $query;
Use actual quotation marks to delimit strings:使用实际的引号来分隔字符串:
$query = "SELECT * FROM Units WHERE ID = '{$uniqueUnits[a]}'"; // ^ quote // ^ PHP variable interpolation
try尝试
$query = "SELECT * FROM Units WHERE ID = '$uniqueUnits[a]'";
^--- ^---
Backticks are for escaping reserved words, so mysql is translating your variable's contents into a field name.反引号用于 escaping 保留字,因此 mysql 将变量的内容转换为字段名称。
Because apparently $uniqueUnits[a] resolves to the empty string.因为显然 $uniqueUnits[a] 解析为空字符串。 And there is no column like this in the database.
并且数据库中没有这样的列。
Try surrounding your array with {}
, like this:尝试用
{}
包围您的数组,如下所示:
$query = "SELECT * FROM Units WHERE ID = `{$uniqueUnits[a]}`";
Also, is column ID
actually in your table?另外,列
ID
实际上在您的表中吗?
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