php - MySQL 和 PHP : querying 3 rows at a time

Question

我正在使用数据库开发照片库。在一切重置之前，每行显示 3 个图像。它将位于 <img>/<img>/<img>/<div> 中格式。

因此，当查看源代码时，您会得到:

<img src="1" alt="">
<img src="2" alt="">
<img src="3" alt="">
<div class="clear-both"></div>

并且它会对数据库中的每一行不断重复此操作。所以 9 张图像将是:

<img src="1" alt="">
<img src="2" alt="">
<img src="3" alt="">
<div class="clear-both"></div>
<img src="4" alt="">
<img src="5" alt="">
<img src="6" alt="">
<div class="clear-both"></div>
<img src="7" alt="">
<img src="8" alt="">
<img src="9" alt="">
<div class="clear-both"></div>

我想我可以使用 while来处理这个问题。但我不知道要添加什么SQL或PHP语句。我考虑过使用WHERE , GROUP BY和COUNT ，但这些都不起作用。

如果可能的话，我还希望它能够处理仅包含 1 个和 2 个图像的行。意思是如果表中有4行，那么它会显示:

<img src="1" alt="">
<img src="2" alt="">
<img src="3" alt="">
<div class="clear-both"></div>
<img src="4" alt="">
<div class="clear-both"></div>

如果有 8 个，则会显示:

<img src="1" alt="">
<img src="2" alt="">
<img src="3" alt="">
<div class="clear-both"></div>
<img src="4" alt="">
<img src="5" alt="">
<img src="6" alt="">
<div class="clear-both"></div>
<img src="7" alt="">
<img src="8" alt="">
<div class="clear-both"></div>

感谢您的帮助。

PHP

$Database4 = new mysqli("localhost", "user", "pass", "Photography");
$Photos = $Database4 -> query("SELECT *
                               FROM `Year2016`
                               -- ORDER BY DateTaken
                               ;");

while ($DataRows = $Photos -> fetch_array()) {
 echo '<img src="photography/small/' . $DataRows["file"] . '" alt="">' . "\n";
}

echo '<div class="clear-both"></div>' . "\n";

SQL

CREATE TABLE `Year2016`(
 `file` text COLLATE utf8_bin NOT NULL,
)
ENGINE = InnoDB
DEFAULT CHARSET = utf8
COLLATE = utf8_bin;

INSERT INTO `Year2016`(`file`)
VALUES
('red-1.png'),
('red-2.png'),
('red-3.png'),
('red-4.png'),
('red-5.png'),
('red-6.png');

Answer 1

这很简单:

$i = 1;    // special counter
while ($DataRows = $Photos -> fetch_array()) {
    echo '<img src="photography/small/' . $DataRows["file"] . '" alt="">' . "\n";
    if ($i % 3 == 0) {
        echo '<div class="clear-both"></div>';
    }
    $i++;
}
// the last one if last `$i` value is not divided by 3
if ($i % 3 != 1) {
    echo '<div class="clear-both"></div>';
}