从数据库中获取数据，并在数组中移位和添加新值 - Fetch data from database and shift and add new value in an array

Fetch data from database and shift and add new value in an array

在数据库表中我有值列。有超过50行。在php中，我有一个固定的10个数组。首先将从数据库中取出10行并存储到数组中。当数组已满时，第11个值将尝试插入数组，第0个值将移动，第11个值将插入数组。例如QUEUE进程。

一开始会显示

[[0,17.9999],[1,13.898],...[9,16.98]]

则[0,17.9999] will move and [10,11.88]将插入并打印如下

[[1,13.898],.......[9,16.98],[10,11.88]]

然后

[2,17.84],......[10,11.88],[11,999]]

等等…

如何在php中表示?

下面是我的代码:

<?php
include("md.php");
$sql = "SELECT * from datatable";
$result =oci_parse($conn, $sql);
$r=oci_execute($result);
$arr = array();
$i=0;
while($row = oci_fetch_array($stid,OCI_ASSOC)){
  $arr[] = array_shift(array($i++, (float)$row['VALUE']));
}
echo json_encode($arr);
?>

请帮。

如果数组中总是有10个键，请尝试

 $arr=array_slice($arr,1,9);
 $arr[]=$row['VALUE'];

而不是

$arr[] = array_shift(array($i++, (float)$row['VALUE']));

注意，当你已经有一个包含10个元素的数组时，它是正确的。请看下面的例子

$arr = array(1,2,3,4,5,6,7,8,9,10);
echo json_encode($arr)."<br>";    
$con = mysqli_connect('127.0.0.1','app_user2','qwe123','test');
$select="select id from adv where id > 300 and id < 312;";
$res = mysqli_query($con, $select);                      
while ($row=$res->fetch_assoc()) {
    $arr=array_slice($arr,1,9);
    $arr[]=$row['id'];
    echo json_encode($arr)."<br>";
}

在浏览器中表示为

[1,2,3,4,5,6,7,8,9,10]
[2,3,4,5,6,7,8,9,10,"301"]
[3,4,5,6,7,8, 9,10,"301","302"]
[4,5,6,7,8,9,10,"301","302","303"]
[5,6,7,8,9,10,"301","302","303","304"]
[6,7,8,9,10,"301","302","303","304","305"]
[7,8,9,10,"301","302","303","304","305","306"]
[8,9,10,"301","302","303","304","305","306","307"]
[9,10,"301","302","303","304","305","306","307","308"]
[10,"301","302","303","304","305","306","307","308","309"]
["301","302","303","304","305","306","307","308","309","310"]
["302","303","304","305","306","307","308","309","310","311"]

如果我理解的话，在50个条目中你只会得到10个，而第11个是将数组的第一个值推走…这就像得到最后10个结果一样，你不觉得吗?

通过承认你的表有一个自动递增的'id'字段:

<?php
include("md.php");
// I've changed your SQL query by adding a reverse sort
// on the 'id' field and put a limit of 10 entries
$sql = "SELECT * from datatable ORDER BY id DESC LIMIT 0,10";
$result =oci_parse($conn, $sql);
$r=oci_execute($result);
$arr = array();
$i=0;
while($row = oci_fetch_array($stid, OCI_ASSOC)){
  $arr[] = (float)$row['VALUE'];
}
echo json_encode($arr);
?>

我还没有测试过这个代码片段，但它应该可以正常工作;)

编辑:如果Ilya的答案是你想做的，请忽略D: