PHP函数从数据库中提取字段值

Question

我正在尝试使用 php 函数获取 mysql 数据库的值。 我有一个这样的数据库：

NAME     | EMAIL                | PASSWORD  | OTHER
-------------------------------------------------------
example  | example@example.com  | password  | other
-------------------------------------------------------
example2 | example2@example.com | password2 | other2

在我的 PHP 文件中，我尝试使用此函数：

function selectUserField($email, $field, $connection){
    $select_user = "SELECT '$field' FROM users WHERE email='$email' LIMIT 1";
    $result = mysqli_query($connection, $select_user);
    $value = mysqli_fetch_assoc($result);
    return $value[$field];
}

//And I try to echo the result of the function
$connection = new mysqli(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME);

echo selectUserField("example@example.com", "name", $connection);

但结果我只得到了字段名称而不是它的内容（对于这个例子，我得到“NAME”而不是“example”）。如何获取数据库单元格的内容？

Answer 1

试试这个

function selectUserField($email, $field, $connection){
    $select_user = "SELECT `$field` FROM users WHERE `email`='$email' LIMIT 1"; //wrap it with ` around the field or don't wrap with anything at all
    $result = mysqli_query($connection, $select_user);
    $value = mysqli_fetch_assoc($result);
    return $value[$field];
}

//And I try to echo the result of the function
$connection = new mysqli(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME);

echo selectUserField("example@example.com", "name", $connection);

Answer 2

$field 周围没有引号。

"SELECT $field FROM users WHERE email='$email' LIMIT 1";