我使用mysqli_num_rows命令使用php mysqli select记录，但它的值为空

Question

我想用“ mysqli_num_rows”计数记录，但是在测试这段代码后我遇到了一些问题

$sql    = "SELECT * FROM users WHERE users_name = 'abc'";
$query  = mysqli_query($conn, $sql);
echo $row    = mysqli_num_rows($query);

result => 1

但是在向SQL插入新条件“ OR”时

$sql    = "SELECT * FROM users WHERE users_name = 'abc' OR users_phone = '12345678'";
$query  = mysqli_query($conn, $sql);
echo $row    = mysqli_num_rows($query);

result => empty value

我的表有2行

users_id = 1,
users_name = abc
users_phone = ''

and

users_id = 2,
users_name = efg
users_phone = 12345678

如果复制sql以在phpMyAdmin中测试正确，则满足2条记录