如何在SQL Server中将数据收集到单行

Question

I have table Risks and history table Risks_history . In Risks table i have data like below:

-----------------------------
| ID | DealID | Description |
-----------------------------
| 1  | 14     | Risk1       |
-----------------------------
| 2  | 14     | Risk2       |
-----------------------------
| 3  | 14     | Risk3       |
-----------------------------
| 4  | 15     | Risk4       |
-----------------------------

So here is we can see that one deal can have several Risks. I need to save data of table Risks in history like below:

-------------------------------------
| ID | dealID |   AllDescriptions   |   
-------------------------------------
| 1  | 14     | Risk1, Risk2, Risk3 |
-------------------------------------
| 2  | 15     | Risk4               |
-------------------------------------

I need trigger that will do it. But now I cant.

How I can collect data from several rows into one row?

EDIT:

I need trigger, so now i have below trigger:

      INSERT INTO [dbo].[Risks_history]
      (
            DealID,
            [AllDescription]
      )
      SELECT 
            [DealID],
            stuff((select ',' + i.name from inserted i
                   where i.DealID= i2.DealID
                   FOR XML PATH('')),1,1,'') as Description                                          
        FROM inserted i2;

But in table Risks_history i have data(which trigger wrote) like below:

 - When I change Risk1:

    -------------------------------------
    | ID | dealID |   AllDescriptions   |   
    -------------------------------------
    | 1  | 14     | Risk1, Risk1, Risk1 |
    -------------------------------------

 - When I change Risk2:

-------------------------------------
| ID | dealID |   AllDescriptions   |   
-------------------------------------
| 1  | 14     | Risk2, Risk2, Risk2 |
-------------------------------------

 - When I change Risk3:

-------------------------------------
| ID | dealID |   AllDescriptions   |   
-------------------------------------
| 1  | 14     | Risk3, Risk3, Risk3 |
-------------------------------------

But I need to write all Risks whatever risk changing

Answer 1

create table #c

( ID int, DealID int, Description varchar(10))
insert into #c values
(1,14,'Risk1'),
(2,14,'Risk2'),
(3,14,'Risk3'),
(4,15,'Risk4')

SELECT DISTINCT DealID,
                STUFF((SELECT ','+Description   
                       FROM #c t1 
                       WHERE t1.DealID = t2.DealID 
                        FOR XML PATH(''))
                       ,1,1,'') as Description   
FROM #c t2

Answer 2

Try this,

SELECT 
  ID,
  STUFF((
    SELECT ', '  + CAST(Description AS VARCHAR(MAX)) 
    FROM Risks
    WHERE (ID = RiskMain.ID) 
FOR XML PATH (''), TYPE), 1, 2, '') AS AllDescriptions  
FROM Risks RiskMain
GROUP BY ID

Answer 3

Please try this..

SELECT DISTINCT
      DealID
    , STUFF((
        SELECT N', ' + CAST([Description] AS VARCHAR(4000))
        FROM Risks R2
        WHERE R1.DealID = R2.DealID
        FOR XML PATH (''), TYPE), 1, 2, '') AS AllDescriptions   
FROM Risks R1
GROUP BY DealID

Your modified trigger and assuming DealID and Description are column names of Risks tables,

DECLARE @DealID INT;

SELECT 
    @DealID = [DealID]                                         
FROM inserted;

INSERT INTO [dbo].[Risks_history]
      (
            DealID,
            [AllDescription]
      )
      SELECT 
            [DealID],
            STUFF((
                SELECT ', ' + R2.[Description]
                FROM Risks R2
                WHERE R1.DealID = R2.DealID
                FOR XML PATH (''), TYPE), 1, 2, '') AS AllDescriptions                                        
        FROM Risks R1
        WHERE DealID = @DealID
    GROUP BY DealID

Answer 4

DECLARE @tblTest AS TABLE
 (
   ID  INT,
   DealID INT,
   Description VARCHAR(50)
 )  

 INSERT INTO @tblTest VALUES(1,14,'Risk1')
 ,(2,14,'Risk2')
 ,(3,14,'Risk3')
 ,(4,15,'Risk4')

 SELECT STUFF((SELECT distinct ',' + QUOTENAME(Description) 
            FROM @tblTest c
            --WHERE c.DealID=T.DealID   
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')

 SELECT
    ROW_NUMBER() OVER (ORDER BY MAX(T.ID)) AS ID,
    T.DealID,
    (SELECT STUFF((SELECT distinct ',' + Description 
            FROM @tblTest c
            WHERE c.DealID=T.DealID 
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')) AS AllDescriptions
FROM @tblTest T
GROUP BY T.DealID

Answer 5

You can get this output with one single SQL query like this:

SELECT t1.DealID,
Descriptions =REPLACE( (SELECT Description AS [data()]
FROM Risks_history t2
WHERE t2.DealID = t1.DealID
ORDER BY Description
FOR XML PATH('')
), ' ', ',')
FROM Risks_history t1
GROUP BY DealID ;

Now you have to put this query under the trigger to insert filter data into your table.

Answer 6

We can use MIN in the ID and DealID in GROUP BY:

SELECT MIN(u.ID) AS ID, 
    u.DealID,
    STUFF((SELECT ', ' + A.Description FROM Mytable A
    WHERE A.DealID=u.DealID FOR XML PATH('')),1,1,'') As [Description]
FROM Mytable u
GROUP BY u.DealID