php - WHERE之后可以在Mysql查询中使用变量吗

Question

以下查询有效并返回结果

$query = "SELECT * FROM table WHERE District = '" . $var . "' ORDER BY Form_Date DESC";

好像我用变量替换单词“District”，它不起作用

$query = "SELECT * FROM table WHERE '" . $distvar . "' = '" . $var . "' ORDER BY Form_Date DESC";

这个有什么问题，我怎样才能让它工作？

Answer 1

删除您正在测试的字段周围的引号，或用反引号替换它们，以免 mysql 解析器误认为它是一个潜在的保留字：

$query = "SELECT * FROM `table` WHERE `" . $distvar . "` = '" . $var . "' ORDER BY Form_Date DESC";

Answer 2

试试这个 ：

$query = "SELECT * FROM table WHERE `" . $distvar . "` = '" . $var . "' ORDER BY Form_Date DESC";

或者

$query = "SELECT * FROM table WHERE " . $distvar . " = '" . $var . "' ORDER BY Form_Date DESC";