Question

所以我想做2个while循环，因为我有2个表。在第一个表格中，我希望得到前5个ID

`$sql = "SELECT * FROM link WHERE `userid`= $uid ORDER by clicks DESC LIMIT 5";`

不要介意Ik声明中的变量是不安全的，所以我稍后会使用预备语句。但是，在第一次它应该给出前5个ID时，在第二个时它会给出5-10。第二个$ sql应该是什么样的？

Answer 1

你需要像这样使用OFFSET：

SELECT * FROM link WHERE `userid`= $uid ORDER by clicks DESC LIMIT 5 OFFSET 5

Answer 2

第二个SQL看起来像这样：

<?php
    ...
    $sql2 = "SELECT * FROM link WHERE userid = :uid ORDER by clicks DESC LIMIT 5 OFFSET 5";

    $stmt = $pdo->prepare(sql2);

    $stmt->execute(['uid ' => $uid]);
    ...
?>

Answer 3

尝试这个。

$sql = "SELECT * FROM link WHERE `userid`= '$uid' ORDER by clicks DESC LIMIT 5, 5";

这将从记录号6开始提供5条记录（记录号5不会出现在结果中）

Answer 4

在1个查询中使用2个循环。不需要额外的查询。

例如在for循环中：

<?php
    $results = array("a","b","c","d","e","f","g","h","i","j","k","l","m","n");

    for($i=0; $i<5; $i++) {
        echo $results[$i];
    }

    echo " / ";

    for ($i=5; $i<10; $i++) {
        echo $results[$i];
    }
    // yields: abcde / fghij
?>

或while循环中的相同示例：

<?php
    $results = array("a","b","c","d","e","f","g","h","i","j","k","l","m","n");
    $i = 0;
    while($i < 5) {
        echo $results[$i];
        $i++;
    } 

    echo " / "; 

    while($i < 10) {
        echo $results[$i];
        $i++;
    } 
    // yields: abcde / fghij
?>

如何在DESC MySQL中选择数字5-10

4 个答案: