Magento获取Zend_Db_Select对象中的SQL语句

 

app/code/core/Mage/Catalog/Model/Resource/Eav/Mysql4/Config.php

/**
 * Retrieve Product Attributes Used in Catalog Product listing
 *
 * @return array
 */
public function getAttributesUsedInListing() {
    $select = $this->_getReadAdapter()->select()
        ->from(array('main_table' => $this->getTable('eav/attribute')))
        ->join(
            array('additional_table' => $this->getTable('catalog/eav_attribute')),
            'main_table.attribute_id = additional_table.attribute_id',
            array()
        )
        ->joinLeft(
             array('al' => $this->getTable('eav/attribute_label')),
            'al.attribute_id = main_table.attribute_id AND al.store_id = ' . (int) $this->getStoreId(),
            array('store_label' => new Zend_Db_Expr('IFNULL(al.value, main_table.frontend_label)'))
        )
        ->where('main_table.entity_type_id=?', $this->getEntityTypeId())
        ->where('additional_table.used_in_product_listing=?', 1);

    // $sql = $select->assemble();
    // echo $sql;

    return $this->_getReadAdapter()->fetchAll($select);
}

 

Magento 操作数据库是在 Zend DB（Zend Framework）的基础上简单的做了下封装了。Zend DB 有自己的一套规则，来组合生成最终的SQL查询语句，可以看到上面的代码中有 from() join() joinLeft() where() 等函数，乱七八糟的一大堆东西，需要对 Zend DB的规则非常熟悉，才能知道实际执行的SQL语句，有没有办法直接打印出SQL语句？找了下，还真有，就是assemble()函数。在上面代码中最后部分可以看到。

顺被把SQL也附上来：

 

SELECT main_table.*,
IFNULL(al.value, main_table.frontend_label) AS store_label
FROM eav_attribute AS main_table
INNER JOIN catalog_eav_attribute AS additional_table
ON main_table.attribute_id = additional_table.attribute_id
LEFT JOIN eav_attribute_label AS al
ON al.attribute_id = main_table.attribute_id AND al.store_id = 1
WHERE (main_table.entity_type_id=’4′)
AND (additional_table.used_in_product_listing=1)

 

 

 

FROM:http://www.sqlstudy.com/article/magento-zend-db-select-sql-output.html