Oracle query to LINQ

Question

我们正在将数据层从预言机迁移到实体框架。 我尝试在 LINQ 中编写此预言机查询

SELECT *
FROM (SELECT   ld203_entity_id, ld203_entity_nm
FROM f.ld203_ent_lst
WHERE ld203_ent_nm <> 'Other' and LD203_ENT_HIDE='Y'
ORDER BY ld203_ent_nm ASC)
UNION ALL
SELECT *
FROM (SELECT   ld203_ent_id, ld203_ent_nm
FROM f.ld203_ent_list 
WHERE ld203_ent_nm = 'Other' and LD203_ENT_HIDE='Y'
ORDER BY ld203_ent_nm ASC);   

LINQ 查询正在尝试..

var ls =
(from a in context.ld203_entity_list
where (a.ld203_entity_nm != "Other" && a.ld203_entity_hide == "Y")
select a.ld203_entity_id, a.ld203_entity_nm)
.Union
(from b in context.ld203_entity_list
where b.ld203_entity_nm == "Other" && b.ld203_entity_hide == "Y"
select b.ld203_entity_id, b.ld203_entity_nm);
dt = LINQResultToDataTable(ls);

任何人都可以帮助在 LINQ C# 中重写它的方法吗？

Answer 1

您可以使用匿名类型来使用Union，如下所示：

var ls = (from a in context.ld203_entity_list
where (a.ld203_entity_nm != "Other" && a.ld203_entity_hide == "Y")
select new { Id = a.ld203_entity_id, Num = a.ld203_entity_nm } )
.Union
(from b in context.ld203_entity_list
where b.ld203_entity_nm == "Other" && b.ld203_entity_hide == "Y"
select new { Id = b.ld203_ent_id, Num = b.ld203_ent_nm});

请注意，所有属性都是在所有实例中声明的，并且它们必须具有相同的数据类型。(例如，在您的情况下，这些ld203_entity_id和ld203_ent_id的数据类型必须相同(

有关详细信息，请查看：创建新的匿名类型列表以合并到现有匿名类型列表