如何使用ORDER BY FIELD对magento产品集合进行排序

我有一个自定义产品属性，实际上有三个可能的值“Frühjahr/ Sommer”，“Herbst / Winter”，“”（空）。
我希望按照预定的顺序按此值对产品集合进行排序，例如“Frühjahr/ Sommer”，“Herbst / Winter”，“”或“Herbst / Winter”，“Frühjahr/ Sommer”，“”
这是交替的。
空值应该在结尾处，但可能还有更多值，因此它必须是固定的预定义顺序。
我需要执行以下MySQL ORDER BY FIELD（saison，“Frühjahr/ Sommer”，“Herbst / Winter”，“”）
问题是我不知道如何在Magento中执行此命令。
我知道“ - > setOrder”-Method但我需要提交一个固定的顺序而不是使用DESC或ASC

不幸的是它不起作用我之前尝试过：

$this->_collection->getSelect()->order(new Zend_Db_Expr("FIELD(season, 'Frühjahr/Sommer','Herbst/Winter','')"));

结果是“处理您的请求时出错。

$this->_collection->getSelect();

返回：

SELECT `e`.*, `cat_index`.`position` AS `cat_index_position`, `price_index`.`price`, `price_index`.`tax_class_id`, `price_index`.`final_price`, IF(price_index.tier_price IS NOT NULL, LEAST(price_index.min_price, price_index.tier_price), price_index.min_price) AS `minimal_price`, `price_index`.`min_price`, `price_index`.`max_price`, `price_index`.`tier_price` FROM `catalog_product_entity` AS `e` INNER JOIN `catalog_category_product_index` AS `cat_index` ON cat_index.product_id=e.entity_id AND cat_index.store_id=1 AND cat_index.visibility IN(2, 4) AND cat_index.category_id='124' INNER JOIN `catalog_product_index_price` AS `price_index` ON price_index.entity_id = e.entity_id AND price_index.website_id = '1' AND price_index.customer_group_id = 0 ORDER BY FIELD(season, 'Frühjahr/Sommer','Herbst/Winter','')

我在phpMyAdmin中执行了这个sql语句，并在'order clause'中收到以下错误消息“Unknown column' season'”

如果我按“季节”DESC订购

$this->_collection->setOrder('season', 'DESC');

它工作...并生成以下sql语句

SELECT `e`.*, `cat_index`.`position` AS `cat_index_position`, `price_index`.`price`, `price_index`.`tax_class_id`, `price_index`.`final_price`, IF(price_index.tier_price IS NOT NULL, LEAST(price_index.min_price, price_index.tier_price), price_index.min_price) AS `minimal_price`, `price_index`.`min_price`, `price_index`.`max_price`, `price_index`.`tier_price`, IF(season_option_value_t2.value_id IS NULL, season_option_value_t1.value, season_option_value_t2.value) AS `season` FROM `catalog_product_entity` AS `e` INNER JOIN `catalog_category_product_index` AS `cat_index` ON cat_index.product_id=e.entity_id AND cat_index.store_id=1 AND cat_index.visibility IN(2, 4) AND cat_index.category_id='124' INNER JOIN `catalog_product_index_price` AS `price_index` ON price_index.entity_id = e.entity_id AND price_index.website_id = '1' AND price_index.customer_group_id = 0 LEFT JOIN `catalog_product_entity_int` AS `season_t1` ON e.entity_id=season_t1.entity_id AND season_t1.attribute_id='180' AND season_t1.store_id=0 LEFT JOIN `catalog_product_entity_int` AS `season_t2` ON e.entity_id=season_t2.entity_id AND season_t2.attribute_id='180' AND season_t2.store_id='1' LEFT JOIN `eav_attribute_option_value` AS `season_option_value_t1` ON season_option_value_t1.option_id=IF(season_t2.value_id > 0, season_t2.value, season_t1.value) AND season_option_value_t1.store_id=0 LEFT JOIN `eav_attribute_option_value` AS `season_option_value_t2` ON season_option_value_t2.option_id=IF(season_t2.value_id > 0, season_t2.value, season_t1.value) AND season_option_value_t2.store_id=1 ORDER BY `season` DESC

但这是DESC的顺序，而不是像我想要的预定义顺序，所以我不能使用它。

我需要的是上面的SQL语句

ORDER BY FIELD(season, 'Frühjahr/Sommer','Herbst/Winter','')

代替

ORDER BY `season` DESC

最后我找到了解决方案。也许其他用户需要它，所以这里是：

（可能不是最好的解决方案，但它有效）

我创建了一个新的Modul并扩展了Mage_Catalog_Block_Product_List_Toolbar。然后我重写“setCollection”-Method就像这样

public function setCollection($collection)
{
    $this->_collection = $collection;

    $this->_collection->setCurPage($this->getCurrentPage());

    // we need to set pagination only if passed value integer and more that 0
    $limit = (int)$this->getLimit();
    if ($limit) {
        $this->_collection->setPageSize($limit);
    }
    if ($this->getCurrentOrder()) {
        $mySource = $this->_collection->getEntity()->getAttribute('season');

        $mySource = $this->_collection->getEntity()->getAttribute('season')->getSource(); //Mage_Eav_Model_Entity_Attribute_Source_Table
        $collection = $this->_collection;
        $valueTable1    = 'season_t1';
        $valueTable2    = 'season_t2';

        $collection->getSelect()
            ->joinLeft(
                array($valueTable1 => $mySource->getAttribute()->getBackend()->getTable()),
                "e.entity_id={$valueTable1}.entity_id"
                . " AND {$valueTable1}.attribute_id='{$mySource->getAttribute()->getId()}'"
                . " AND {$valueTable1}.store_id=0",
                array()
            )
            ->joinLeft(
                array($valueTable2 => $mySource->getAttribute()->getBackend()->getTable()),
                "e.entity_id={$valueTable2}.entity_id"
                . " AND {$valueTable2}.attribute_id='{$mySource->getAttribute()->getId()}'"
                . " AND {$valueTable2}.store_id='{$collection->getStoreId()}'",
                array()
            );
        $valueExpr = $collection->getSelect()->getAdapter()
        ->getCheckSql("{$valueTable2}.value_id > 0", "{$valueTable2}.value", "{$valueTable1}.value");

        Mage::getResourceModel('eav/entity_attribute_option')
            ->addOptionValueToCollection($collection, $mySource->getAttribute(), $valueExpr);

        $sortBySeason = "FIELD(IF(season_option_value_t2.value_id IS NULL, season_option_value_t1.value, season_option_value_t2.value), ";


        $getSelectedSeason = Mage::getStoreConfig('sortproductsbyseason_options/general/current_season');

        if($getSelectedSeason == "herbst_winter"){
            $sortBySeason .= "'Frühjahr/Sommer', 'Herbst/Winter' ,''";
        }else{
            $sortBySeason .= "'Herbst/Winter', 'Frühjahr/Sommer' ,''";
        }
        $sortBySeason .= ") DESC";

        $this->_collection->getSelect()->order(new Zend_Db_Expr($sortBySeason));

        $this->_collection->setOrder($this->getCurrentOrder(), $this->getCurrentDirection());
    }

    return $this;
}