请求对我不起作用

Question

我不明白为什么这个请求不起作用。

$query ="UPDATE $this->tabdata SET ";
foreach ($this->dataedit as $key => $value) {
 $query .= "".$key."  = '".$value."', ";
}

$pat ="+-0*/";
$query .= $pat;
$query = str_replace(", ".$pat," ", $query)  ;
$query .=" WHERE  id = '$id' ";
echo $query;
$sql = mysql_query($query);

Answer 1

$query ="UPDATE $this->tabdata SET ";
foreach ($this->dataedit as $key => $value) {
 $query .= "".$key."  = '".$value."', ";
}

$pat ="+-0*/";
$query .= $pat;
$query = str_replace(", ".$pat," ", $query)  ;
$query .=" WHERE  id = '{$id}' ";//modify'$id' to '{$id}',try again 
echo $query;
$sql = mysql_query($query);

链接Strings's single quoted part

注意：与双引号和heredoc语法不同，特殊字符的变量和转义序列在出现在单引号字符串中时不会被扩展。