orderbydescending date linq查询 [英] orderbydescending date linq query

问题描述

我正在尝试查询数据，结果按降序排列。当我查询 - startDate = 04/09 / 2014& endDate = 04/14/2014时，我得到的结果显示从第9个而不是第14个。我不清楚这是如何实现的。这就是我目前所拥有的：



更新代码：

I am trying to query data, where the result is in descending order. When I query -- startDate=04/09/2014&endDate=04/14/2014, I get results showing from the 9th instead the 14th. I am little unclear how is this achievable. This is what I currently have:

Updated Code:

public HttpResponseMessage Get([FromUri] Query query)
        {
                var data = db.database_bd.AsQueryable();

                int pageSize = 10;

                if (query.price_type != null)
                {
                    data = data.Where(c => c.Cover == query.price_type);
                }
                if (query.endDate != null)
                {
                    data = data.Where(c => c.UploadDate <= query.endDate);
                }

                if (query.startDate != null)
                {
                    data = data.Where(c => c.UploadDate >= query.startDate);
                }
                

                // If any other filters are specified, return records which match any of them:
                var filteredData = new List<IQueryable<database_bd>>();

                if (!string.IsNullOrEmpty(query.name))
                {
                    var ids = query.name.Split(',');
                    foreach (string i in ids)
                    {
                        filteredData.Add(data.Where(c => c.Name != null && c.Name.Contains(i)));
                    }
                }

                if (filteredData.Count != 0)
                {
                    data = filteredData.Aggregate(Queryable.Union);
                }

                if (!data.Any())
                {
                    var message = string.Format("No data was found");
                    return Request.CreateErrorResponse(HttpStatusCode.NotFound, message);
                }
                int total = data.Count();

		data = data.OrderByDescending(c => c.UploadDate).Take(10);

                if (filteredData.Count != 0)
                {
                    data = data.OrderByDescending(d => d.UploadDate).Take(pageSize);
                }

                //return Request.CreateResponse(HttpStatusCode.OK, data);
                return Request.CreateResponse(HttpStatusCode.OK, new { total, data });
            }

对此的任何建议都非常感谢。非常感谢。

Any advice on this would be very much appreciated. Many thanks.

推荐答案

if（query.price_type！= null）

{

data = data。 OrderByDescending（d => d.UploadDate）。取（10）;

}



if（query.endDate！= null）

{

data = data.OrderByDescending（c => c.UploadDate< = query.endDate）.Take（10）;

}



if（query.startDate！= null）

{

data = data.OrderByDescending（ c => c.UploadDate> = query.startDate）。取（10）;



}

if（filteredData.Count ！= 0）

{

data = data.OrderByDescending（d => d.UploadDate）。取（10）;

}



用以下代码替换它。



data = data.OrderByDescending（c => c.UploadDate）。取（10）;



因为您已经在方法的顶部添加了过滤器。因此，您不应该按顺序再次执行此操作。

if (query.price_type != null)
{
data = data.OrderByDescending(d => d.UploadDate).Take(10);
}

if (query.endDate != null)
{
data = data.OrderByDescending(c => c.UploadDate <= query.endDate).Take(10);
}

if (query.startDate != null)
{
data = data.OrderByDescending(c => c.UploadDate >= query.startDate).Take(10);

}
if (filteredData.Count != 0)
{
data = data.OrderByDescending(d => d.UploadDate).Take(10);
}

replace that with below code.

data = data.OrderByDescending(c => c.UploadDate).Take(10);

Because you have already added filters at the top of the method. SO you should not do it again in the order by.

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