php - Zend Framework 分组案例

Question

我在使用 zend 框架 mysql groupby 查询时遇到问题。我想要实现的是这个查询

SELECT * FROM `price_list` AS `pl` 
GROUP BY 
CASE WHEN `pl`.`sub_folder` IS NULL THEN 
`pl`.`id` 
ELSE 
`pl`.`sub_folder` 
END 
ORDER BY `pl`.`date_added` DESC

这是我用 zend 方式尝试的

$sql = $this->select()->setIntegrityCheck(false);       
$sql->from(array('pl'=>$this->_name), array(''))
    ->columns($cols)
    ->group("case when pl.sub_folder is null then pl.id else pl.sub_folder end");

但是在 case 条件下输出带有错误引号的 sql 字符串:

SELECT * FROM `price_list_pdf` AS `pl` 
GROUP BY `CASE WHEN pl`.`sub_folder is null then 
pl`.`id 
ELSE
pl`.`sub_folder 
end` 
ORDER BY `pl`.`date_added` DESC

如何清除字符串中的这个`？或者有什么更好的方法吗？请帮助..

Answer 1

对于未转义的查询，使用Expressions like

$sql = $this->select()->setIntegrityCheck(false);       
$sql->from(array('pl'=>$this->_name), array(''))
        ->columns($cols)
        ->group(new Zend_Db_Expr("case when pl.sub_folder is null then pl.id else pl.sub_folder end"));