無法刪除第一個逗號在字符串的SQL Server

Question

的代碼工作正常，除了

SELECT DISTINCT isnull(@FEATURE + ', ', ',') + Feature 
    FROM [128.100.194.219, 1435].[EMSData].[dbo].[vOSLRoomFeatures] as rf2 where (rf2.roomid = rf.roomid) 
    for xml path('')), 

這是給我的問題。我不知道如何擺脫第一個逗號。我試過了substring，但它刪除了所有的逗號（我猜是因爲它在select語句中）。我甚至試過 COALESCE（@FEATURE +'，'，''）+ FEATURE但我最終得到的結果是相同的，無論是末尾還是最開始都沒有逗號或一個額外的逗號。

DECLARE @FEATURE VARCHAR(500) 
-- INSERT INTO BookableRooms IF NOT EXISTS ROOM NUMBER 
INSERT INTO dbo.BookableRooms_test (FK_Building_code, 
            Room_num,Other_room_name, 
            Capacity_from, 
            Capacity_to, 
            Accessiblity,AV_book_separate,Flooring_type,Features, 
            Food_drink_allowed, Alcohol_allowed,Internet, 
            [Owner],FK_BookingContact_ID, 
            LCD_projector,Computer,FK_SpaceManager_code,Last_updated_date,Last_updated_by,SpecialFlag) 
SELECT DISTINCT CASE 
      WHEN rf.[Building Reference] is null or rf.[Building Reference] = '' THEN 'HH' 
      ELSE rf.[Building Reference] 
     END, 
     [ROOMID],[Description], 
     (SELECT MIN(rf2.CAPACITY) FROM [128.100.194.219, 1435].[EMSData].[dbo].[vOSLRoomFeatures] AS rf2 WHERE rf2.ROOMID = rf.ROOMID), 
     (SELECT MAX(rf2.CAPACITY) FROM [128.100.194.219, 1435].[EMSData].[dbo].[vOSLRoomFeatures] AS rf2 WHERE rf2.ROOMID = rf.ROOMID), 
     dbo.iszero([Wheelchair Accessible]), dbo.iszero(rf.[Separate AV]),dbo.isflat(rf.[Flat Floor]), 
     (
     SELECT DISTINCT isnull(@FEATURE + ', ', ',') + Feature 
     FROM [128.100.194.219, 1435].[EMSData].[dbo].[vOSLRoomFeatures] as rf2 where (rf2.roomid = rf.roomid) 
     for xml path('')), 
     dbo.iszero(rf.[Food and Drink]),dbo.iszero(rf.[Alcohol]),dbo.iszero(rf.[Room Internet]), 
     'HH',5, 
     dbo.iszero(rf.[Digital Projector]),dbo.iszero(rf.[Computer]),'HH',GetDate(),'System',dbo.iszero(rf.[Restricted]) 

FROM [128.100.194.219, 1435].[EMSData].[dbo].[vOSLRoomFeatures] as rf where NOT EXISTS(
    SELECT 1 FROM dbo.BookableRooms_test b WHERE 
    b.Room_num = rf.ROOMID); 

Answer 1

使用的東西，但在子查詢的外側：

stuff ((SELECT DISTINCT ',' + Feature 
     FROM [128.100.194.219, 1435].[EMSData].[dbo].[vOSLRoomFeatures] as rf2 
     WHERE (rf2.roomid = rf.roomid) 
     for xml path('')), 1, 1, '') 

Answer 2

我不知道你在努力達到什麼目的。如果我的猜測是錯誤的，那麼如果你告訴我們你在哪種情況下會得到什麼結果，那就太好了。

試試這個

CASE WHEN @FEATURE IS NULL THEN NULL ELSE @FEATURE + ', ' END 

Answer 3

使用STUFF功能刪除前導逗號。

SELECT DISTINCT STUFF(',' + Feature 
    FROM [128.100.194.219, 1435].[EMSData].[dbo].[vOSLRoomFeatures] as rf2 where (rf2.roomid = rf.roomid) 
    for xml path('')),1,1,''),