php - 获取sql记录

Question

当我运行此代码时，它会很好地返回主题...

$query = mysql_query("SELECT topic
FROM question 
WHERE id = '$id'");
    if(mysql_num_rows($query) > 0) {
        $row = mysql_fetch_array($query) or die(mysql_error());
        $topic = $row['topic'];
    }

但是当我把它改成这个时，它根本不运行。为什么会这样？

$query = mysql_query("SELECT topic, lock
FROM question 
WHERE id = '$id'");
    if(mysql_num_rows($query) > 0) {
        $row = mysql_fetch_array($query) or die(mysql_error());
        $topic = $row['topic'];
        $lockedThread = $row['lock'];
        echo "here: " . $lockedThread;
    }

Answer 1

确保lock不是 MySQL 关键字（保留字），您可能需要`lock`在字段列表中将其反引号 ( )：

SELECT `topic`, `lock`
...

MySQL 5.6 保留字