SQL不返回數據

Question

我想返回@from和@to之間的數據。 DB中的日期是nvarchar（max）類型。 Sql很好，因爲當我設置@from和@to並在sql server中運行sql代碼時，返回正確的結果。 XML不爲空，有列名稱，但不包含列數據。

public static DataSet Report(string from, string to) 
{ 
    DataSet ds = new DataSet("Rez"); 
    using (SqlConnection conn = new SqlConnection(conf.ConnStrVienaSas)) 
    { 
     using (SqlCommand cmd = new SqlCommand(FileReaderHelper.ReadSQLText("ExternalReports.sql"), conn)) 
     { 
      cmd.CommandType = CommandType.Text; 
      cmd.CommandTimeout = 180; 
      cmd.Parameters.Add("@from", SqlDbType.NVarChar).Value = from; 
      cmd.Parameters.Add("@to", SqlDbType.NVarChar).Value = to; 
      using (SqlDataAdapter adap = new SqlDataAdapter(cmd)) 
      try 
      { 
       adap.Fill(ds); 
      } 
      catch (Exception ex) 
      { 
       ds = WSErrorExtenderHelper.CreateErrorDS(ex.ToString() /*"Error reading data from DB."*/); 
      } 
     } 
    } 
    return ds; 
} 

SQL片段：

SELECT [A].[FieldValue] AS Created_at, [B].[Created_by], [C].[Code1], 
[D].[Code2], [E].[Code3], [F].[Code4] 
FROM [dbo].[TEMP] A with (nolock) 
INNER JOIN [dbo].[TEMP2] B with (nolock) 
ON [A].[UserDefinedRowId] = [B].[UserDefinedRowId] 
INNER JOIN [dbo].[TEMP3] C with (nolock) 
ON [A].[UserDefinedRowId] = [C].[UserDefinedRowId] 
INNER JOIN [dbo].[TEMP4] D with (nolock) 
ON [A].[UserDefinedRowId] = [D].[UserDefinedRowId] 
INNER JOIN [dbo].[TEMP5] E with (nolock) 
ON [A].[UserDefinedRowId] = [E].[UserDefinedRowId] 
INNER JOIN [dbo].[TEMP6] F with (nolock) 
ON [A].[UserDefinedRowId] = [F].[UserDefinedRowId] 

WHERE ([A].[FieldValue] between @from and @to) 

Answer 1

我相信使用：

conn.Open(); 

將解決你的問題