我有两张桌子，想知道是否可以将它们加入一个查询中。
脚本获得catID作为GET，它应该列出所有的subCats（如果有的话），然后列出mainCat cat = catID and subcat = 0中的照片
subCats表是：
id | parentCat | title | addedBy | date | active | defaultPhoto
photos表格为：id | title | description | fileName | fileType | uploadedBy | time | cat | subCat
我有一个分页脚本，需要计数并生成LIMIT才能使用。想知道我是否可以将这个结合到两个表的一个查询中，一些如何使我已经获得的分页更容易。因此，使用连接选择两者的计数，然后另一个选择结果。
有什么想法吗？真的坚持这个。
这是我糟糕的开始，但到目前为止似乎是一个糟糕的设计：
<?php
if ($catInfoResult = $db->select("SELECT * FROM cats WHERE id = '%s' LIMIT 1", $catID))
{
if ($db->numRows > 0)
{
$pageTitle = h($catInfoResult[0]['title']) . ' - Photo Gallery';
?>
<div class="headingTitle"><?=h($catInfoResult[0]['title'])?> Photos</div>
<?php
//get subCats
$subCatCountResult = $db->count('subCats', '*', array('parentCat' => $catID));
if (is_numeric($subCatCountResult))
{
$PerPage = 9; //how many locations you want to show per page
$subCatLastPage = ceil($subCatCountResult/$PerPage);
if ($subCatLastPage < 1)
{
$subCatLastPage = 1;
}
$pageNum = (isset($_GET['pg'])) ? trim($_GET['pg']) : 1;
$pageNum = preg_replace('#[^0-9]#', '', $pageNum);
//////////////////////////////////////////////////
$subCatLimit = 'LIMIT ' . ($pageNum - 1) * $PerPage . ',' . $PerPage;
//////////////////////////////////////////////////
$itemList = array(
'subCats' => array(),
'photos' => array()
);
if ($subCatListResult = $db->select("SELECT * FROM subCats WHERE parentCat = %s ORDER BY title $subCatLimit", $catID))
{
if ($db->numRows > 0)
{
foreach ($subCatListResult as $row)
{
$photoID = 0;
if ($row['defaultPhoto'] == 0) //look up photo for
{
if ($firstPhotoResult = $db->select("SELECT id, time FROM photos WHERE subCat = '%s' ORDER BY time ASC LIMIT 1", $row['id']))
{
if ($db->numRows > 0)
{
$photoID = $firstPhotoResult[0]['id'];
}
else
{
$photoID = -1;
}
}
}
else
{
$photoID = $row['defaultPhoto'];
}
//add to $itemList
$itemList['subCats'][$row['id']] = array(
'title' => $row['title']
);
$itemList['subCats'][$row['id']]['defaultPhoto'] = $photoID;
}
}
}
else
{
throwDBError();
}
function addPhotoToItemList($row)
{
global $itemList;
$itemList['photos'][$row['id']] = array(
'title' => $row['title'],
'fileName' => $row['fileName'],
'fileType' => $row['fileType']
);
//
}
//get photos after subcats
$photosOffset = 0;
$grabPhotosCount = 9 - count($itemList['subCats']);
if ($grabPhotosCount > 0)
{
if ($result = $db->select("SELECT * FROM photos WHERE cat = %s and subCat = 0 ORDER BY title LIMIT 0, $grabPhotosCount", $catID))
{
if ($db->numRows > 0)
{
foreach ($result as $row)
{
$photosOffset++;
addPhotoToItemList($row);
}
}
}
else
{
throwDBError();
}
}
//get photos in maincat
$photosCountResult = $db->count('photos', '*', array('cat' => $catID, 'subCat' => 0));
if (is_numeric($photosCountResult))
{
}
else
{
throwDBError();
}
if ($pageNum < 1)
{
$pageNum = 1;
}
else if ($pageNum > $subCatLastPage) //get photos
{
if (count($itemList) < 9)
{
//load in photos for cat
}
//redirect('/gallery/?cat=' . $catID . '&pg=' . $lastPage);
}
//pagination
$totalCounts = $grabPhotosCount + $subCatCountResult;
$lastPage = ceil($totalCounts/$PerPage);
if ($lastPage < 1)
{
$lastPage = 1;
}
$pageNum = (isset($_GET['pg'])) ? trim($_GET['pg']) : 1;
$pageNum = preg_replace('#[^0-9]#', '', $pageNum);
}
else
{
throwDBError();
}
echo '<pre>';
print_r($itemList);
echo '</pre>';
}
else
{
echo '<div align="center">Category not found.</div>';
}
}
else
{
throwDBError();
}
?>
答案 0 :(得分：0)
您可以创建行号变量，然后从该派生表中进行选择。对你的桌面结构进行了一次尝试，这样的事情可以起作用：
SELECT *
FROM (
SELECT p.id,
p.title,
sc.title as subcat_title,
@curRow := @curRow + 1 AS row_number
FROM photos p
INNER JOIN subCats sc on p.subcat = sc.id
INNER JOIN (SELECT @curRow := 0) r
) AS tbl
WHERE row_number>3 AND row_number<=6
在WHERE子句中设置开始和结束分页行数。