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/* 获取价格分级 */
if ($cat['grade'] == 0 && $cat['parent_id'] != 0)
{
$cat['grade'] = get_parent_grade($cat_id); //如果当前分类级别为空，取最近的上级分类
}
if ($cat['grade'] > 1)
{
/* 需要价格分级 */
/*
算法思路：
1、当分级大于1时，进行价格分级
2、取出该类下商品价格的最大值、最小值
3、根据商品价格的最大值来计算商品价格的分级数量级：
价格范围(不含最大值) 分级数量级
0-0.1 0.001
0.1-1 0.01
1-10 0.1
10-100 1
100-1000 10
1000-10000 100
4、计算价格跨度：
取整((最大值-最小值) / (价格分级数) / 数量级) * 数量级
5、根据价格跨度计算价格范围区间
6、查询数据库
可能存在问题：
1、
由于价格跨度是由最大值、最小值计算出来的
然后再通过价格跨度来确定显示时的价格范围区间
所以可能会存在价格分级数量不正确的问题
该问题没有证明
2、
当价格=最大值时，分级会多出来，已被证明存在
*/
$sql = "SELECT min(g.shop_price) AS min, max(g.shop_price) as max ".
" FROM " . $ecs->table('goods'). " AS g ".
" WHERE ($children OR " . get_extension_goods($children) . ') AND g.is_delete = 0 AND g.is_on_sale = 1 AND g.is_alone_sale = 1 ';
//获得当前分类下商品价格的最大值、最小值
$row = $db->getRow($sql);
// 取得价格分级最小单位级数，比如，千元商品最小以100为级数
$price_grade = 0.0001;
for($i=-2; $i<= log10($row['max']); $i++)
{
$price_grade *= 10;
}
//跨度
$dx = ceil(($row['max'] - $row['min']) / ($cat['grade']) / $price_grade) * $price_grade;
if($dx == 0)
{
$dx = $price_grade;
}
for($i = 1; $row['min'] > $dx * $i; $i ++);
for($j = 1; $row['min'] > $dx * ($i-1) + $price_grade * $j; $j++);
$row['min'] = $dx * ($i-1) + $price_grade * ($j - 1);
for(; $row['max'] >= $dx * $i; $i ++);
$row['max'] = $dx * ($i) + $price_grade * ($j - 1);
$sql = "SELECT (FLOOR((g.shop_price - $row[min]) / $dx)) AS sn, COUNT(*) AS goods_num ".
" FROM " . $ecs->table('goods') . " AS g ".
" WHERE ($children OR " . get_extension_goods($children) . ') AND g.is_delete = 0 AND g.is_on_sale = 1 AND g.is_alone_sale = 1 '.
" GROUP BY sn ";
$price_grade = $db->getAll($sql);
foreach ($price_grade as $key=>$val)
{
$temp_key = $key + 1;
$price_grade[$temp_key]['goods_num'] = $val['goods_num'];
$price_grade[$temp_key]['start'] = $row['min'] + round($dx * $val['sn']);
$price_grade[$temp_key]['end'] = $row['min'] + round($dx * ($val['sn'] + 1));
$price_grade[$temp_key]['price_range'] = $price_grade[$temp_key]['start'] . ' - ' . $price_grade[$temp_key]['end'];
$price_grade[$temp_key]['formated_start'] = price_format($price_grade[$temp_key]['start']);
$price_grade[$temp_key]['formated_end'] = price_format($price_grade[$temp_key]['end']);
$price_grade[$temp_key]['url'] = build_uri('category', array('cid'=>$cat_id, 'bid'=>$brand, 'price_min'=>$price_grade[$temp_key]['start'], 'price_max'=> $price_grade[$temp_key]['end'], 'filter_attr'=>$filter_attr_str), $cat['cat_name']);
/* 判断价格区间是否被选中 */
if (isset($_REQUEST['price_min']) && $price_grade[$temp_key]['start'] == $price_min && $price_grade[$temp_key]['end'] == $price_max)
{
$price_grade[$temp_key]['selected'] = 1;
}
else
{
$price_grade[$temp_key]['selected'] = 0;
}
}
$price_grade[0]['start'] = 0;
$price_grade[0]['end'] = 0;
$price_grade[0]['price_range'] = $_LANG['all_attribute'];
$price_grade[0]['url'] = build_uri('category', array('cid'=>$cat_id, 'bid'=>$brand, 'price_min'=>0, 'price_max'=> 0, 'filter_attr'=>$filter_attr_str), $cat['cat_name']);
$price_grade[0]['selected'] = empty($price_max) ? 1 : 0;
$smarty->assign('price_grade', $price_grade);
}
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