检查查询是否返回零行

Question

我正在使用此代码，但是我不明白查询是否返回零行。我该如何检查？

$results = $mysqli->query("SELECT ANNOUNCE_NUMBER,ANNOUNCEMENTS,ANNOUNCE_TYPE,POST_DATE FROM home ORDER BY ANNOUNCE_NUMBER DESC");
while ($obj = $results->fetch_object()) {
    //output results from database
}

Answer 1

您可以使用数据集中的num_rows检查返回的行数。示例：

$results = $mysqli->query("SELECT ANNOUNCE_NUMBER,ANNOUNCEMENTS,ANNOUNCE_TYPE,POST_DATE FROM home ORDER BY ANNOUNCE_NUMBER DESC");
if ($results->num_rows === 0) {
    echo 'No results';
} else {
    while ($obj = $results->fetch_object()) {
        //output results from database
    }
}