Question

我正在尝试运行一个返回到自定义对象的简单自定义查询，但是，我一直遇到错误而且我不知道出了什么问题。该查询在SQL Server Management Studio中运行良好。

public class MyClass
{
    public Nullable<int> EligibleCredits { get; set;}
    public Nullable<int> ReadyForSubmissionCredits { get; set; }
    public Nullable<int> RedeemedCredits { get; set; }
}

主要方法：

var query = @"SELECT 
    (select count(*) from MyTable where UserId = @userId and [Status] = 0 and Year(EarnDate) >= (select Year(getdate()) -@years)) as EligibleCredits,
    (select count(*) from MyTable where UserId = @userId and [Status] = 1 and Year(EarnDate) >= (select Year(getdate()) -@years)) as ReadyForSubmissionCredits,
    (select count(*) from MyTable where UserId = @userId and [Status] = 2 and Year(EarnDate) >= (select Year(getdate()) -@years)) as RedeemedCredits";

var objectQuery = new ObjectQuery<MyClass>(query, ((IObjectContextAdapter)this).ObjectContext);
objectQuery.Parameters.Add(new ObjectParameter("userId", userId));
objectQuery.Parameters.Add(new ObjectParameter("years", years));

return objectQuery.FirstOrDefault();

我得到的错误是：

查询语法无效。近期＆＃39; *＆＃39;，第2行，第39栏。

此查询在SQL Server Management Studio中正常运行。

另外，根据这篇文章，我正确地做到了：https://msdn.microsoft.com/en-us/library/bb738521(v=vs.100).aspx

Answer 1

这是EntityFramework查询解析器中的错误。我所能做的就是为你提供一种解决方法（BTW，甚至可以更快地运行）：

var query = @"SELECT 
    ISNULL(SUM(CASE WHEN [Status] = 0 THEN 1 ELSE 0 END),0) as EligibleCredits,
    ISNULL(SUM(CASE WHEN [Status] = 1 THEN 1 ELSE 0 END),0) as ReadyForSubmissionCredits,
    ISNULL(SUM(CASE WHEN [Status] = 2 THEN 1 ELSE 0 END),0) as RedeemedCredits
    FROM MyTable 
       WHERE UserId = @userId 
       AND Year(EarnDate) >= Year(getdate()) - @years";

var objectQuery = new ObjectQuery<MyClass>(query, ((IObjectContextAdapter)this).ObjectContext);
objectQuery.Parameters.Add(new ObjectParameter("userId", userId));
objectQuery.Parameters.Add(new ObjectParameter("years", years));

return objectQuery.FirstOrDefault();

请注意，如果this是DbContext的实例，您可以按如下方式简化代码：

var query = @"SELECT 
    ISNULL(SUM(CASE WHEN [Status] = 0 THEN 1 ELSE 0 END),0) as EligibleCredits,
    ISNULL(SUM(CASE WHEN [Status] = 1 THEN 1 ELSE 0 END),0) as ReadyForSubmissionCredits,
    ISNULL(SUM(CASE WHEN [Status] = 2 THEN 1 ELSE 0 END),0) as RedeemedCredits
    FROM MyTable 
       WHERE UserId = @p0 -- <== NOTE THE PARAM NAME HERE AND BELOW
       AND Year(EarnDate) >= Year(getdate()) - @p1";
return new this.Database.SqlQuery<MyClass>(query, userId, years).FirstOrDefault();

最后一种方法也适用于原始查询。

Answer 2

ExecuteStoreQuery 为我工作，同样的错误。示例如下：

IList<MyClass> contactList =
            (((IObjectContextAdapter) model).ObjectContext.ExecuteStoreQuery<MyClass>(strString))
            .ToList<MyClass>();

实体框架错误 - 查询语法无效

2 个答案: