EF4 LINQ - 在联接上添加过滤

发布于 2024-10-27 07:19:56 字数 420 浏览 1 评论 0原文

如何在 LINQ 中将 FILTER CLAUSE 添加到 JOIN TABLE ....？

<块引用>
AND t2.Public = 1 AND t2.Color = '蓝色'

SELECT t1.ID, t1.Name, (SELECT COUNT(*) 
                      FROM tbl2 t2 
                     WHERE t2.ID = t1.ID 
                       AND t2.Public = 1 AND t2.Color = 'Blue') AS MyCount 
 FROM tbl1 t1
WHERE t1.State = 'CA'

原文

How do I add a FILTER CLAUSE to a JOIN TABLE ....in LINQ ?

AND t2.Public = 1 AND t2.Color = 'Blue'

SELECT t1.ID, t1.Name, (SELECT COUNT(*) 
                      FROM tbl2 t2 
                     WHERE t2.ID = t1.ID 
                       AND t2.Public = 1 AND t2.Color = 'Blue') AS MyCount 
 FROM tbl1 t1
WHERE t1.State = 'CA'

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吹梦到西洲 2024-11-03 07:19:56

它应该看起来像这样。

from t1 in context.tbl1
where t1.State = "CA"
select new 
{
    t1.ID, 
    t1.Name,
    MyCount = t1.tbl2s.Count(t2 => t2.Public && t2.Color == "Blue")
}

这就是我在不了解上下文中实体的名称、它们之间的关系以及它们的标量值的类型的情况下可以提供的所有帮助。

It should look something like this.

from t1 in context.tbl1
where t1.State = "CA"
select new 
{
    t1.ID, 
    t1.Name,
    MyCount = t1.tbl2s.Count(t2 => t2.Public && t2.Color == "Blue")
}

That's about all the help I can give without knowing more about the names of the entities in your context, their relationships to each other, and the types of their scalar values.

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萌化 2024-11-03 07:19:56

如果您的实体之间没有导航属性，请使用：

var data = from t1 in context.Tbl1
           join t2 in context.Tbl2 on t1.Id equals t2.Id
           where t1.State = "CA" && t2.Public == 1 && t2.Color = "Blue"
           group t1 by new { t1.Id, t1.Name } into g
           select new 
               {
                   Id = g.Key.Id,
                   Name = g.Key.Name,
                   Count = g.Count()
               };

如果它们具有导航属性，请使用 @StriplingWarrior 提供的解决方案

If your entities don't have navigation property between them use:

var data = from t1 in context.Tbl1
           join t2 in context.Tbl2 on t1.Id equals t2.Id
           where t1.State = "CA" && t2.Public == 1 && t2.Color = "Blue"
           group t1 by new { t1.Id, t1.Name } into g
           select new 
               {
                   Id = g.Key.Id,
                   Name = g.Key.Name,
                   Count = g.Count()
               };

If they have navigation properties use solution provided by @StriplingWarrior

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