PHP＆amp; SQL：WHERE MATCH查找两列或更多列

Question

使用WHERE MATCH在两列或多列中查找完全匹配时遇到一些困难。在我尝试的脚本下面：

SELECT * FROM people WHERE MATCH (_fristname) AGAINST ('$search') LIMIT 0, 2;

上面的代码工作正常，

SELECT * FROM people WHERE MATCH (_lastname) AGAINST ('$search') LIMIT 0, 2;

上面的代码也有效，

SELECT * FROM people WHERE MATCH (_firstname, _lastname) AGAINST ('$search') LIMIT 0, 2;

上面的代码不起作用。我想在两列中搜索完全匹配

以下代码是我以前用PHP输出的代码：

$searched = mysqli_query($connect, $sql);
while($info = mysqli_fetch_array($searched)) {
   echo $info['_jobdescription'];
}