하위 쿼리의 여러 결과를 단일 쉼표로 구분 된 값으로 결합

하위 쿼리의 여러 결과를 단일 쉼표로 구분 된 값으로 결합

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두 개의 테이블이 있습니다.

TableA
------
ID,
Name

TableB
------
ID,
SomeColumn,
TableA_ID (FK for TableA)

관계는 하나 개의 행 TableA의 많은 - TableB.

이제 다음과 같은 결과를보고 싶습니다.

ID     Name      SomeColumn

1.     ABC       X, Y, Z (these are three different rows)
2.     MNO       R, S

이것은 작동하지 않습니다 (여러 결과가 하위 쿼리에 있음).

SELECT ID,
       Name, 
       (SELECT SomeColumn FROM TableB WHERE F_ID=TableA.ID)
FROM TableA

클라이언트 측에서 처리하면 사소한 문제입니다. 그러나 이것은 모든 페이지에서 X 쿼리를 실행해야 함을 의미합니다. 여기서 X는의 결과 수입니다 TableA.

의 행에 대해 여러 결과를 반환하므로 단순히 GROUP BY 또는 이와 유사한 작업을 수행 할 수 없습니다 TableA.

COALESCE 또는 이와 유사한 것을 활용하는 UDF가 작동하는지 확실하지 않습니까?

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이것조차도 목적을 달성 할 것입니다

샘플 데이터

declare @t table(id int, name varchar(20),somecolumn varchar(MAX))
insert into @t
    select 1,'ABC','X' union all
    select 1,'ABC','Y' union all
    select 1,'ABC','Z' union all
    select 2,'MNO','R' union all
    select 2,'MNO','S'

질문:

SELECT ID,Name,
    STUFF((SELECT ',' + CAST(T2.SomeColumn AS VARCHAR(MAX))
     FROM @T T2 WHERE T1.id = T2.id AND T1.name = T2.name
     FOR XML PATH('')),1,1,'') SOMECOLUMN
FROM @T T1
GROUP BY id,Name

산출:

ID  Name    SomeColumn
1   ABC     X,Y,Z
2   MNO     R,S

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1. UDF를 만듭니다.

CREATE FUNCTION CombineValues
(
    @FK_ID INT -- The foreign key from TableA which is used 
               -- to fetch corresponding records
)
RETURNS VARCHAR(8000)
AS
BEGIN
DECLARE @SomeColumnList VARCHAR(8000);

SELECT @SomeColumnList =
    COALESCE(@SomeColumnList + ', ', '') + CAST(SomeColumn AS varchar(20)) 
FROM TableB C
WHERE C.FK_ID = @FK_ID;

RETURN 
(
    SELECT @SomeColumnList
)
END

2. 하위 쿼리에서 사용 :

SELECT ID, Name, dbo.CombineValues(FK_ID) FROM TableA

3. 저장 프로 시저를 사용하는 경우 다음과 같이 할 수 있습니다.

CREATE PROCEDURE GetCombinedValues
 @FK_ID int
As
BEGIN
DECLARE @SomeColumnList VARCHAR(800)
SELECT @SomeColumnList =
    COALESCE(@SomeColumnList + ', ', '') + CAST(SomeColumn AS varchar(20)) 
FROM TableB
WHERE FK_ID = @FK_ID 

Select *, @SomeColumnList as SelectedIds
    FROM 
        TableA
    WHERE 
        FK_ID = @FK_ID 
END

---

I think you are on the right track with COALESCE. See here for an example of building a comma-delimited string:

http://www.sqlteam.com/article/using-coalesce-to-build-comma-delimited-string

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In MySQL there is a group_concat function that will return what you're asking for.

SELECT TableA.ID, TableA.Name, group_concat(TableB.SomeColumn) 
as SomColumnGroup FROM TableA LEFT JOIN TableB ON 
TableB.TableA_ID = TableA.ID

---

You may need to provide some more details for a more precise response.

Since your dataset seems kind of narrow, you might consider just using a row per result and performing the post-processing at the client.

So if you are really looking to make the server do the work return a result set like

ID       Name       SomeColumn
1        ABC        X
1        ABC        Y
1        ABC        Z
2        MNO        R
2        MNO        S

which of course is a simple INNER JOIN on ID

Once you have the resultset back at the client, maintain a variable called CurrentName and use that as a trigger when to stop collecting SomeColumn into the useful thing you want it to do.

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Assuming you only have WHERE clauses on table A create a stored procedure thus:

SELECT Id, Name From tableA WHERE ...

SELECT tableA.Id AS ParentId, Somecolumn 
FROM tableA INNER JOIN tableB on TableA.Id = TableB.F_Id 
WHERE ...

Then fill a DataSet ds with it. Then

ds.Relations.Add("foo", ds.Tables[0].Columns("Id"), ds.Tables[1].Columns("ParentId"));

Finally you can add a repeater in the page that puts the commas for every line

 <asp:DataList ID="Subcategories" DataKeyField="ParentCatId" 
DataSource='<%# Container.DataItem.CreateChildView("foo") %>' RepeatColumns="1"
 RepeatDirection="Horizontal" ItemStyle-HorizontalAlign="left" ItemStyle-VerticalAlign="top" 
runat="server" >

In this way you will do it client side but with only one query, passing minimal data between database and frontend

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I tried the solution priyanka.sarkar mentioned and the didn't quite get it working as the OP asked. Here's the solution I ended up with:

SELECT ID, 
        SUBSTRING((
            SELECT ',' + T2.SomeColumn
            FROM  @T T2 
            WHERE WHERE T1.id = T2.id
            FOR XML PATH('')), 2, 1000000)
    FROM @T T1
GROUP BY ID

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Solution below:

SELECT GROUP_CONCAT(field_attr_best_weekday_value)as RAVI
FROM content_field_attr_best_weekday LEFT JOIN content_type_attraction
    on content_field_attr_best_weekday.nid = content_type_attraction.nid
GROUP BY content_field_attr_best_weekday.nid

Use this, you also can change the Joins

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SELECT t.ID, 
       t.NAME, 
       (SELECT t1.SOMECOLUMN 
        FROM   TABLEB t1 
        WHERE  t1.F_ID = T.TABLEA.ID) 
FROM   TABLEA t; 

This will work for selecting from different table using sub query.

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I have reviewed all the answers. I think in database insertion should be like:

ID     Name      SomeColumn
1.     ABC       ,X,Y Z (these are three different rows)
2.     MNO       ,R,S

The comma should be at previous end and do searching by like %,X,%

참고URL : https://stackoverflow.com/questions/111341/combine-multiple-results-in-a-subquery-into-a-single-comma-separated-value