php - 选择 10 组查询

Question

我点击此处的一个链接，并相应地修改了我的代码。我想要实现的目标是，例如表名 media_ids 包含 45 行(这是动态的)，我想将行数划分为最少 10 行的组(在我的情况下，四组 10 行和 1 组) 5)并每小时执行每组代码。

例如，从 id 1 到 10 选择记录，然后从 11 到 20 选择第二个小时，依此类推，除非获取最后一条记录并从 id 1 重新开始。

我添加了一个跟踪器，它检查当前限制并继续。但它给了我想要实现的所需结果。

<?php
require('inc/dbConnect.php');

$lastPointerq = "select tracker from media_tracker";
$lastPointerResult = mysqli_query($con, $lastPointerq);
$lastPointerRes = mysqli_fetch_row($lastPointerResult);
$lastPointer = $lastPointerRes[0];
$lastPointer10=$lastPointer+10;

$currentMediaQuery = "select * from media_ids where id > ".$lastPointer." limit ".$lastPointer.",".$lastPointer10."";

$mediaQuery = mysqli_query($con, $currentMediaQuery);

if (mysqli_num_rows($mediaQuery) > 0) {
    while ($row = mysqli_fetch_assoc($mediaQuery)) {
       // do stuff…
      echo $id=$row['id']."<br>";
    }
}

else
{echo "0";}

if ($lastPointer + 10 > 40) {
    $lastPointer = 1;
} else {
    $lastPointer += 10;
}

mysqli_query($con, "update media_tracker set tracker = $lastPointer");
?>

Answer 1

我假设您每小时通过 ajax/Js 调用这个脚本... 在你的代码中，如果你从另一个脚本中删除一些数据，你可能会发现你的第一行 id 即 100 !

require('inc/dbConnect.php');

$limit = 10 ;
$lastPointerq = "select tracker from media_tracker";
$lastPointerResult = mysqli_query($con, $lastPointerq);
$lastPointerRes = mysqli_fetch_row($lastPointerResult);
$lastPointer = $lastPointerRes[0];

$lastPointerRes = mysqli_fetch_assoc($lastPointerResult);
$lastPointer = empty($lastPointerRes['tracker']) ?  0 : $lastPointerRes['tracker'] ;

$lastPointer10=$lastPointer* $limit;

$currentMediaQuery = "select * from media_ids  limit ".$limit." OFFSET  ".$lastPointer10."";

$mediaQuery = mysqli_query($con, $currentMediaQuery);

if (mysqli_num_rows($mediaQuery) > 0) {
    while ($row = mysqli_fetch_assoc($mediaQuery)) {
       // do stuff…
      echo $id=$row['id']."<br>";
    }
}

else
{echo "0";}

//do a total row count query here and set  as value of $total rather than 40
$total =40 ;
$flag = ceil($total/$limit);

if ($lastPointer == $flag) {
    $lastPointer = 0;
} else {
    $lastPointer ++;
}

mysqli_query($con, "update media_tracker set tracker = $lastPointer");