在dbCommand.CommandText中按大小寫排序

Question

我試圖在dbcommand.commandtext中通過case語句添加一個order，但是我看到沒有行被返回。我想爲case語句中的顏色分配優先級。這將幫助我避免創建一個新的表來優先考慮，並重寫很多代碼來映射外鍵。任何輸入都會有幫助。

這裏的語句： -

Protected Sub AddData() 
    Dim cn As OleDbConnection = New OleDbConnection(ConfigurationManager.AppSettings("ConnectionString")) 
    cn.Open() 
    Dim dbCommand As New OleDbCommand 
    dbCommand.Connection = cn 

    dbCommand.CommandText = "SELECT * from tblPosts ORDER BY CASE PriorityLevel WHEN 'Red' then 1 when 'Orange' then 2 ELSE 3 END" 

    Try 
     dbCommand.ExecuteNonQuery() 
     Dim objdatareader As OleDbDataReader = dbCommand.ExecuteReader() 
     While objdatareader.Read() 
      Dim PostID As Integer = CInt(objdatareader("ID")) 
      PopulateImages(PostID, cn) 
      PopulateCategories(PostID, cn) 
      rssFeed.AddItem(objdatareader, ImageList, CategoryList) 
      ImageList.Clear() 
      CategoryList.Clear() 
     End While 

     objdatareader.Close() 
    Catch myerror As OleDbException 
     Dim strErr As String = "There was an error updating the database: " & myerror.Message 
    End 

謝謝

Answer 1

，能得到任何異常？由於您有END PriorityLevel，所以出現語法錯誤。在END不會帶來任何語法錯誤後，刪除PriorityLevel。

除此之外，您的陳述看起來是正確的。

這工作：

declare @tblPosts table(
    PriorityLevel varchar(10) 
) 

    insert into @tblPosts 
    values('Orange'),('Red'),('Green'),('Orange') 

    SELECT * from @tblPosts ORDER BY 
    CASE PriorityLevel WHEN 'Red' then 1 
        when 'Orange' then 2 
    ELSE 3 END 

這不起作用：

declare @tblPosts table(
    PriorityLevel varchar(10) 
) 

    insert into @tblPosts 
    values('Orange'),('Red'),('Green'),('Orange') 

    SELECT * from @tblPosts ORDER BY CASE 
    PriorityLevel WHEN 'Red' then 1 
       when 'Orange' then 2 
    ELSE 3 END PriorityLevel