SQL聯盟未能

Question

SELECT TOP 5 
    Notices.Id, 
    NoticeLoc.Notices_Id, 
    Loc.Id as Loc_Id, 
    CAST(Notices.Text AS TEXT) as Text, 
    CAST(Notices.Title AS TEXT) as Title, 
    Notices.CDate as RDate 
FROM NoticeLoc 
    JOIN Notices ON NoticeLoc.Notices_Id=Notices.Id JOIN Loc ON NLoc.Loc_Id=Loc.Id WHERE Loc_Id IN (1) 

UNION 

SELECT TOP 5 
    Notices.Id, 
    '', 
    '', 
    CAST(Notices.Text AS TEXT) as Text, 
    CAST(Notices.Title AS TEXT) as Title, 
    Notices.CDate as RDate 
FROM NoticeC 
    JOIN Notices ON NoticeC.Notices_Id=Notices.Id WHERE C_Id=110 AND CDate BETWEEN '10/01/2011' AND '07/14/2025' ORDER BY RDate desc 

我試圖使用MSSQL 2個的結果集之間進行聯合，但是我收到以下錯誤：

Msg 421, Level 16, State 1, Line 1 The text data type cannot be selected as DISTINCT because it is not comparable.

我必須保持這些領域的文本字段。

我該如何解決這個問題，歡呼聲。

Answer 1

UNION本身被解釋爲使用DISTINCT（可能是因爲UNION試圖將兩個查詢固有地網格化爲一個DISTINCT列表）。使用UNION ALL。

Answer 2

問題是數據的類型（TEXT）。你能夠改變表來使用VARCHAR（MAX）嗎？或者從聯合中刪除TEXT字段？或者，也許只是在您的查詢中將字段轉換爲VARCHAR（MAX）？

VARCHAR（MAX）在功能上與文本相同（無限長度，不存儲在行中等）。