如何让我的 LINQ 查询生成我期望的 SQL 语句？

Question

我有一个简单的 Web 表单，其中有 3 个文本框和一个带有搜索按钮的下拉列表。

这是我根据从 4 个控件中选择的输入过滤 EF(4.0) 上下文的代码：

string mFormId = ddlTransValueSearchFormId.SelectedItem.Text.ToString().Trim();
string mControlId = ddlTransValueSearchControlId.SelectedItem.Text.ToString().Trim();
int mTransCategoryId;
try
{
    mTransCategoryId = Int32.Parse(ddlTransValueSearchCategoryId.SelectedItem.Value.ToString());
}
catch(Exception ex)
{
    throw ex;
}
string mDefaultTransValue = tbTransValueSearchDefaultValue.Text.ToString().Trim();

我的 LINQ 查询

TranslationEntity efSchema = new TranslationEntity();
gvTransValues.DataSource = (from defaultValue in efSchema.TRANS_VALUES
                            .Include("TRANS_CATEGORY")
                            where (
                                mFormId == ""            ? 1 == 1 : defaultValue.FormId.Contains(mFormId)
                             && mControlId == ""         ? 1 == 1 : defaultValue.ControlId.Contains(mControlId)
                             && mTransCategoryId == -1   ? 1 == 1 : defaultValue.TransCategoryId == mTransCategoryId
                             && mDefaultTransValue == "" ? 1 == 1 : defaultValue.DefaultTranValue.Contains(mDefaultTransValue)
                             )
                         select new 
                         { 
                            TranValueId = defaultValue.TranValueId,
                            FormId = defaultValue.FormId,
                            ControlId = defaultValue.ControlId,
                            TransCategoryId = defaultValue.TransCategoryId,
                            CategoryName = defaultValue.TRANS_CATEGORY.CategoryName,
                            DefaultTranValue = defaultValue.DefaultTranValue,
                         });
gvTransValues.DataBind();

生成的SQL语句

使用探查器，这是生成的 SQL 查询：

declare @p__linq__0 nvarchar(4000),@p__linq__1 nvarchar(4000),@p__linq__2 nvarchar(4000),@p__linq__3 nvarchar(4000),@p__linq__4 int,@p__linq__5 int,@p__linq__6 nvarchar(4000),@p__linq__7 nvarchar(4000)
SELECT @p__linq__0=N'',@p__linq__1=N'%%',@p__linq__2=N'',@p__linq__3=N'%%',@p__linq__4=1,@p__linq__5=1,@p__linq__6=N'cat',@p__linq__7=N'%cat%'

SELECT 
[Extent1].[TRAN_VALUE_ID] AS [TRAN_VALUE_ID], 
[Extent1].[FORM_ID] AS [FORM_ID], 
[Extent1].[CONTROL_ID] AS [CONTROL_ID], 
[Extent1].[TRANS_CATEGORY_ID] AS [TRANS_CATEGORY_ID], 
[Extent2].[CATEGORY_NAME] AS [CATEGORY_NAME], 
[Extent1].[DEFAULT_TRAN_VALUE] AS [DEFAULT_TRAN_VALUE]
FROM  [dbo].[TRANS_VALUES] AS [Extent1]
LEFT OUTER JOIN [dbo].[TRANS_CATEGORY] AS [Extent2] ON [Extent1].[TRANS_CATEGORY_ID] = [Extent2].[TRANS_CATEGORY_ID]
WHERE 
(CASE 
    WHEN (N'' = @p__linq__0) THEN cast(1 as bit) 
    WHEN (([Extent1].[FORM_ID] LIKE @p__linq__1 ESCAPE N'~') AND (N'' = @p__linq__2)) THEN cast(1 as bit) 
    WHEN (([Extent1].[CONTROL_ID] LIKE @p__linq__3 ESCAPE N'~') AND (-1 = @p__linq__4)) THEN cast(1 as bit) 
    WHEN (([Extent1].[TRANS_CATEGORY_ID] = @p__linq__5) AND (N'' = @p__linq__6)) THEN cast(1 as bit) 
    WHEN ([Extent1].[DEFAULT_TRAN_VALUE] LIKE @p__linq__7 ESCAPE N'~') THEN cast(1 as bit) 
    WHEN ( NOT ([Extent1].[DEFAULT_TRAN_VALUE] LIKE @p__linq__7 ESCAPE N'~')) THEN cast(0 as bit) 
END) = 1

这不是我想要的。无论参数值如何，EF 生成脚本的方式都是从数据库返回所有行。

这里出了什么问题？

我要的SQL语句

事实上，就 SQL 服务器而言，我需要并认为最佳的是让 EF 生成这种查询。

SELECT 
[Extent1].[TRAN_VALUE_ID] AS [TRAN_VALUE_ID], 
[Extent1].[FORM_ID] AS [FORM_ID], 
[Extent1].[CONTROL_ID] AS [CONTROL_ID], 
[Extent1].[TRANS_CATEGORY_ID] AS [TRANS_CATEGORY_ID], 
[Extent2].[CATEGORY_NAME] AS [CATEGORY_NAME], 
[Extent1].[DEFAULT_TRAN_VALUE] AS [DEFAULT_TRAN_VALUE]
FROM  [dbo].[TRANS_VALUES] AS [Extent1]
LEFT OUTER JOIN [dbo].[TRANS_CATEGORY] AS [Extent2] ON [Extent1].[TRANS_CATEGORY_ID] = [Extent2].[TRANS_CATEGORY_ID]
WHERE
    ISNULL([Extent1].[FORM_ID],N'') LIKE '%' + COALESCE(@p__linq__0,[Extent1].[FORM_ID],N'') + '%'
AND ISNULL([Extent1].[CONTROL_ID],N'') LIKE '%' + COALESCE(@p__linq__1,[Extent1].[CONTROL_ID],N'') + '%'    
AND ISNULL([Extent1].[TRANS_CATEGORY_ID],-1) = COALESCE(@p__linq__2,[Extent1].[TRANS_CATEGORY_ID],-1)
AND ISNULL([Extent1].[DEFAULT_TRAN_VALUE],N'') LIKE '%' + COALESCE(@p__linq__3,[Extent1].[DEFAULT_TRAN_VALUE],N'') + '%'    
go

Answer 1

试试这样写：

(from defaultValue in efSchema.TRANS_VALUES
 .Include("TRANS_CATEGORY")
 where (defaultValue.FormId.Contains(mFormId) || mFormId == "")
     && (defaultValue.ControlId.Contains(mControlId) || mControlId == "")
     && (defaultValue.TransCategoryId.Contains(mTransCategoryId) || mTransCategoryId == "")
     && (defaultValue.DefaultTranValue.Contains(mDefaultTransValue) || mDefaultTransValue == ""))

Answer 2

如果您逐步构建查询，这会简单得多。

var query = efSchema.TRANS_VALUES.Include("TRANS_CATEGORY");
if(!string.IsNullOrEmpty(mFormId))
{
    query = query.Where(defaultValue => defaultValue.FormId.Contains(mFormId));
}
if(!string.IsNullOrEmpty(mControlId))
{
    query = query.Where(defaultValue => defaultValue.ControlId.Contains(mControlId));
}
if(mTransCategoryId != -1)
{
    query = query.Where(defaultValue => defaultValue.TransCategoryId == mTransCategoryId);
}
if(!string.IsNullOrEmpty(mDefaultTransValue))
{
    query = query.Where(defaultValue => defaultValue.DefaultTransValue.Contains(mDefaultTransValue));
}

gvTransValues.DataSource = query.Select(defaultValue => new 
                        { 
                            TranValueId = defaultValue.TranValueId,
                            FormId = defaultValue.FormId,
                            ControlId = defaultValue.ControlId,
                            TransCategoryId = defaultValue.TransCategoryId,
                            CategoryName = defaultValue.TRANS_CATEGORY.CategoryName,
                            DefaultTranValue = defaultValue.DefaultTranValue,
                        });

（我认为它应该像这样工作，但您可能必须将 query 的初始类型指定为 IQueryable<YOURTYPE>）

如何让我的 LINQ 查询生成我期望的 SQL 语句？

How do I get my LINQ Query to generate the SQL statement I expect?

c#

sql-server

asp.net

entity-framework

where-clause