OData“，其中列表中的ID”查询 [英] OData "where ID in list" query

问题描述

我有一个OData服务，我想通过ID列表过滤; SQL的等价类似于：

I have an OData service where I'm trying to filter by a list of IDs; the SQL equivalent would be something like:

SELECT * FROM MyTable WHERE TableId IN (100, 200, 300, 400)

我想要过滤的属性是以Int32格式输入的。我试过以下，这给我一个错误操作符'添加'不兼容操作数类型'Edm.String'和'Edm.Int32'：

The property I'm trying to filter on is typed as an Int32. I've tried the following, which gives me an error "Operator 'add' incompatible with operand types 'Edm.String' and 'Edm.Int32'":

string ids = ",100,200,300,400,";
from m in provider.Media where ids.Contains("," + t.media_id + ",")

b $ b

以及

as well as

string ids = ",100,200,300,400,";
from m in provider.Media where ids.Contains("," + t.media_id.ToString() + ",")

和

string ids = ",100,200,300,400,";
from m in provider.Media where ids.Contains("," + Convert.ToString(t.media_id) + ",")

和

string ids = ",100,200,300,400,";
from m in provider.Media where ids.Contains(string.Concat(",", t.media_id, ","))

正如你所看到的，目前我正在使用LINQ来查询服务。

As you can see, currently I'm using LINQ to query the service.

有什么方法可以做我试图，或者我坚持构造一个文本过滤器和使用AddQueryOption，并迭代列表，并手动添加或media_id eq 100子句？

Is there a way I can do what I'm trying to, or am I stuck constructing a text filter and using AddQueryOption, and iterating through the list and manually adding "or media_id eq 100" clauses?

推荐答案

试试这个

 var ids = new [] { 100, 200, 300 } ;
 var res = from m in provider.Media 
           from id in ids 
           where m.media_id == id 
           select m;

有关于 msdn 查询DataServices。

there is a comprehensive description on msdn on querying DataServices.

另一种方法是

var results = provider.Media
   .AddQueryOption("$filter", "media_id eq 100");

，因为OData不支持 IN 您将想出过滤条件的语句如下

and since OData doesn't support IN statements you will come up with filter condition like this

.AddQueryOption("$filter", "(media_id eq 100) or (media_id eq 200 ) or ...");

您可以使用loop或linq建立选择和 string.Join ：

which you can build using loop or linq Select and string.Join:

var ids = new [] { 100, 200, 300 };
var filter = string.Join(" or ", ids.Select(i=> $"(media_id eq {i})"));
var results = provider.Media.AddQueryOption("$filter", filter);

更新：有过滤操作 field = [a，b ] 然而它意味着不同的东西。

UPDATE: There is filter operation field=["a","b"] however it means something different.

UPDATE2：在OData V4中有lambda表达式任何和全部与数组文本 [a，b] 配对，它们可能在中工作，未能在OData.org上提供有关示例v4端点的工作语法。

UPDATE2: In OData V4 there is lambda expressions any and all, paired with array literal ["a", "b"] they might work as in but I failed to come up with working syntax on example v4 endpoint at OData.org

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