在查询中不需要AND选项，因为默认情况下它是AND选项，并且查询仅由“ands”组成

$conditions = array(                                 
    'Product.cost >= ' => $startPrice,                                  
    'Product.cost <= ' => $endPrice,
    'Product.id > ' => $lastid,
    'Product.category' => $category
);

编辑

如果您需要在category中使用OR语句，则只需添加：

$conditions = array(                                 
    'Product.cost >= ' => $startPrice,                                  
    'Product.cost <= ' => $endPrice,
    'Product.id > ' => $lastid,
    'OR' => array(
        'Product.category' => $category,
        'Product.category' => anoter_value
    )
);

您可以在cakephp查询中不包含和的情况下执行此操作。复制代码并尝试执行，尝试查看此代码与您的代码的差异

$lastid = $this->request->data["lastid"];
$startPrice = $this->request->data["startPrice"];
$endPrice = $this->request->data["endPrice"];
$category = $this->request->data["category"];

$conditions = array(                                
            'Product.cost >= ' => $startPrice,                                  
            'Product.cost <= ' => $endPrice,
            'Product.id > ' => $lastid,
             'Product.category' => $category
);

$result = $this->YourModel->find('all', array('conditions' => $conditions));