Question

在我的表单中创建自动递增注册ID时，我需要一些帮助。它可以是数字或字母数字。如果它以aaa0001开头，则我将其显示在表单中。在第一个条目之后，它应该增加到aaa0002并以表格形式显示。我尝试使用JSON和PHP，那里有些错误。可能是aaa0001，aaa0002，...... aaa9999 .... aab0000 ...

PHP

$details = mysqli_query($con, "SELECT MAX(`member_id`) FROM `member_details`");
$details = mysqli_query($con, "SELECT * FROM `member_details` WHERE `member_id` ");

$rows = array();
while ($r = mysqli_fetch_assoc($details)) {
  $rows[] = $r;
}
print json_encode($details);

JSON

var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function() {
  if (this.readyState == 4 && this.status == 200) {
    var myObj = JSON.parse(this.responseText);

    //var memid = myObj[0].member_id;
    //memid++;
    //document.getElementById("member_id").value = memid;
    document.getElementById("member_id").value = myObj[0];
    alert(myObj);
  }
};
xmlhttp.open("GET", "/fetch_reg_memid.php?member_id=" + member_id, true);
xmlhttp.send();
}

Answer 1

首先，您的第一个查询可以，有一个更简单的选择：

FirebaseFirestore rootRef = FirebaseFirestore.getInstance();
CollectionRefference itemsRef = rootRef.collection("items");
Query query = itemsRef.orderBy("date", Query.Direction.ASCENDING);

第二，从mysqli的提取应该是固定的。 details是您用json编码的对象

如果只有一行，那么您不需要遍历所有案例... 所以

$details= mysqli_query($con, "SELECT MAX(`member_id`) FROM `member_details`");
$details = mysqli_query($con, "SELECT member_id FROM `member_details` ORDER BY member_id dESC");

然后$r = mysqli_fetch_assoc($details);应该返回您的member_id：

$r['member_id']

自动递增注册ID

1 个答案: