Mysql全文搜索当column1 = value1且Column2 = value2时

Question

我正在尝试使用 Full Text 搜索书桌  publisher -> example和author -> test ... 或
publisher -> example和auhtor -> test和bookname -> another ...

我试过这个问题：

    $this->_query  = "SELECT " . $targetCol . " FROM " . $this->_dbName . "." . $this->_tableName . " WHERE ";
    $this->_query .= "MATCH(publisher) AGAINST('" . $pub . "') AND ";
    $this->_query .= "MATCH(author) AGAINST('" . $aut . "') ";

但这并不是正确的结果。
我在stackoverflow搜索并发现了类似的内容：

    $this->_query  = "SELECT " . $targetCol . " FROM " . $this->_dbName . "." . $this->_tableName . " WHERE ";
    $this->_query .= "MATCH(publisher, author) AGAINST('" . $pub . "', '" . $aut . "')";

但是这个也没有正确的结果。看来这些查询主要关注第一列publishre in my case

你能告诉我为什么吗？或者我的查询是否符合我的目标？

Thanks in advance