How to concatenate text from multiple rows into a single text string in SQL Server

Question

Consider a database table holding names, with three rows:

Peter
Paul
Mary

Is there an easy way to turn this into a single string of Peter, Paul, Mary?

Answer 1

If you are on SQL Server 2017 or Azure, see Mathieu Renda answer.

I had a similar issue when I was trying to join two tables with one-to-many relationships. In SQL 2005 I found that XML PATH method can handle the concatenation of the rows very easily.

If there is a table called STUDENTS

SubjectID       StudentName
----------      -------------
1               Mary
1               John
1               Sam
2               Alaina
2               Edward

Result I expected was:

SubjectID       StudentName
----------      -------------
1               Mary, John, Sam
2               Alaina, Edward

I used the following T-SQL:

SELECT Main.SubjectID,
       LEFT(Main.Students,Len(Main.Students)-1) As "Students"
FROM
    (
        SELECT DISTINCT ST2.SubjectID, 
            (
                SELECT ST1.StudentName + ',' AS [text()]
                FROM dbo.Students ST1
                WHERE ST1.SubjectID = ST2.SubjectID
                ORDER BY ST1.SubjectID
                FOR XML PATH (''), TYPE
            ).value('text()[1]','nvarchar(max)') [Students]
        FROM dbo.Students ST2
    ) [Main]

You can do the same thing in a more compact way if you can concat the commas at the beginning and use substring to skip the first one so you don't need to do a sub-query:

SELECT DISTINCT ST2.SubjectID, 
    SUBSTRING(
        (
            SELECT ','+ST1.StudentName  AS [text()]
            FROM dbo.Students ST1
            WHERE ST1.SubjectID = ST2.SubjectID
            ORDER BY ST1.SubjectID
            FOR XML PATH (''), TYPE
        ).value('text()[1]','nvarchar(max)'), 2, 1000) [Students]
FROM dbo.Students ST2

Answer 2

This answer may return unexpected results For consistent results, use one of the FOR XML PATH methods detailed in other answers.

Use COALESCE:

DECLARE @Names VARCHAR(8000) 
SELECT @Names = COALESCE(@Names + ', ', '') + Name 
FROM People

Just some explanation (since this answer seems to get relatively regular views):

• Coalesce is really just a helpful cheat that accomplishes two things:

1) No need to initialize @Names with an empty string value.

2) No need to strip off an extra separator at the end.

• The solution above will give incorrect results if a row has a NULL Name value (if there is a NULL, the NULL will make @Names NULL after that row, and the next row will start over as an empty string again. Easily fixed with one of two solutions:

DECLARE @Names VARCHAR(8000) 
SELECT @Names = COALESCE(@Names + ', ', '') + Name
FROM People
WHERE Name IS NOT NULL

or:

DECLARE @Names VARCHAR(8000) 
SELECT @Names = COALESCE(@Names + ', ', '') + 
    ISNULL(Name, 'N/A')
FROM People

Depending on what behavior you want (the first option just filters NULLs out, the second option keeps them in the list with a marker message [replace 'N/A' with whatever is appropriate for you]).

Answer 3

SQL Server 2017+ and SQL Azure: STRING_AGG

Starting with the next version of SQL Server, we can finally concatenate across rows without having to resort to any variable or XML witchery.

STRING_AGG (Transact-SQL)

Without grouping

SELECT STRING_AGG(Name, ', ') AS Departments
FROM HumanResources.Department;

With grouping:

SELECT GroupName, STRING_AGG(Name, ', ') AS Departments
FROM HumanResources.Department
GROUP BY GroupName;

With grouping and sub-sorting

SELECT GroupName, STRING_AGG(Name, ', ') WITHIN GROUP (ORDER BY Name ASC) AS Departments
FROM HumanResources.Department
GROUP BY GroupName;

Answer 4

One method not yet shown via the XML data() command in SQL Server is:

Assume a table called NameList with one column called FName,

SELECT FName + ', ' AS 'data()'
FROM NameList
FOR XML PATH('')

returns:

"Peter, Paul, Mary, "

Only the extra comma must be dealt with.

As adopted from @NReilingh's comment, you can use the following method to remove the trailing comma. Assuming the same table and column names:

STUFF(REPLACE((SELECT '#!' + LTRIM(RTRIM(FName)) AS 'data()' FROM NameList
FOR XML PATH('')),' #!',', '), 1, 2, '') as Brands

Answer 5

In SQL Server 2005

SELECT Stuff(
  (SELECT N', ' + Name FROM Names FOR XML PATH(''),TYPE)
  .value('text()[1]','nvarchar(max)'),1,2,N'')

---

In SQL Server 2016

you can use the FOR JSON syntax

i.e.

SELECT per.ID,
Emails = JSON_VALUE(
   REPLACE(
     (SELECT _ = em.Email FROM Email em WHERE em.Person = per.ID FOR JSON PATH)
    ,'"},{"_":"',', '),'$[0]._'
) 
FROM Person per

And the result will become

Id  Emails
1   abc@gmail.com
2   NULL
3   def@gmail.com, xyz@gmail.com

This will work even your data contains invalid XML characters

the '"},{"_":"' is safe because if you data contain '"},{"_":"', it will be escaped to "},{\"_\":\"

You can replace ', ' with any string separator

---

And in SQL Server 2017, Azure SQL Database

You can use the new STRING_AGG function

Answer 6

In MySQL, there is a function, GROUP_CONCAT(), which allows you to concatenate the values from multiple rows. Example:

SELECT 1 AS a, GROUP_CONCAT(name ORDER BY name ASC SEPARATOR ', ') AS people 
FROM users 
WHERE id IN (1,2,3) 
GROUP BY a

Answer 7

Use COALESCE - Learn more from here

For an example:

102

103

104

Then write the below code in SQL Server,

Declare @Numbers AS Nvarchar(MAX) -- It must not be MAX if you have few numbers
SELECT  @Numbers = COALESCE(@Numbers + ',', '') + Number
FROM   TableName where Number IS NOT NULL

SELECT @Numbers

The output would be:

102,103,104

Answer 8

PostgreSQL arrays are awesome. Example:

Create some test data:

postgres=# \c test
You are now connected to database "test" as user "hgimenez".
test=# create table names (name text);
CREATE TABLE
test=# insert into names (name) values ('Peter'), ('Paul'), ('Mary');
INSERT 0 3
test=# select * from names;
 name
-------
 Peter
 Paul
 Mary
(3 rows)

Aggregate them in an array:

test=# select array_agg(name) from names;
 array_agg
-------------------
 {Peter,Paul,Mary}
(1 row)

Convert the array to a comma-delimited string:

test=# select array_to_string(array_agg(name), ', ') from names;
 array_to_string
-------------------
 Peter, Paul, Mary
(1 row)

DONE

Since PostgreSQL 9.0 it is even easier, quoting from deleted answer by "horse with no name":

select string_agg(name, ',') 
from names;

Answer 9

Oracle 11g Release 2 supports the LISTAGG function. Documentation here.

COLUMN employees FORMAT A50

SELECT deptno, LISTAGG(ename, ',') WITHIN GROUP (ORDER BY ename) AS employees
FROM   emp
GROUP BY deptno;

    DEPTNO EMPLOYEES
---------- --------------------------------------------------
        10 CLARK,KING,MILLER
        20 ADAMS,FORD,JONES,SCOTT,SMITH
        30 ALLEN,BLAKE,JAMES,MARTIN,TURNER,WARD

3 rows selected.

Warning

Be careful implementing this function if there is possibility of the resulting string going over 4000 characters. It will throw an exception. If that's the case then you need to either handle the exception or roll your own function that prevents the joined string from going over 4000 characters.

Answer 10

A recursive CTE solution was suggested, but no code was provided. The code below is an example of a recursive CTE.

Note that although the results match the question, the data doesn't quite match the given description, as I assume that you really want to be doing this on groups of rows, not all rows in the table. Changing it to match all rows in the table is left as an exercise for the reader.

;WITH basetable AS (
    SELECT
        id,
        CAST(name AS VARCHAR(MAX)) name,
        ROW_NUMBER() OVER (Partition BY id ORDER BY seq) rw,
        COUNT(*) OVER (Partition BY id) recs
    FROM (VALUES
        (1, 'Johnny', 1),
        (1, 'M', 2),
        (2, 'Bill', 1),
        (2, 'S.', 4),
        (2, 'Preston', 5),
        (2, 'Esq.', 6),
        (3, 'Ted', 1),
        (3, 'Theodore', 2),
        (3, 'Logan', 3),
        (4, 'Peter', 1),
        (4, 'Paul', 2),
        (4, 'Mary', 3)
    ) g (id, name, seq)
),
rCTE AS (
    SELECT recs, id, name, rw
    FROM basetable
    WHERE rw = 1

    UNION ALL

    SELECT b.recs, r.ID, r.name +', '+ b.name name, r.rw + 1
    FROM basetable b
    INNER JOIN rCTE r ON b.id = r.id AND b.rw = r.rw + 1
)
SELECT name
FROM rCTE
WHERE recs = rw AND ID=4
OPTION (MAXRECURSION 101)

Answer 11

In SQL Server 2005 and later, use the query below to concatenate the rows.

DECLARE @t table
(
    Id int,
    Name varchar(10)
)
INSERT INTO @t
SELECT 1,'a' UNION ALL
SELECT 1,'b' UNION ALL
SELECT 2,'c' UNION ALL
SELECT 2,'d' 

SELECT ID,
stuff(
(
    SELECT ','+ [Name] FROM @t WHERE Id = t.Id FOR XML PATH('')
),1,1,'') 
FROM (SELECT DISTINCT ID FROM @t ) t

Answer 12

I don't have access to a SQL Server at home, so I'm guess at the syntax here, but it's more or less:

DECLARE @names VARCHAR(500)

SELECT @names = @names + ' ' + Name
FROM Names

Answer 13

In SQL Server 2017 or later versions, you can use the STRING_AGG() function to generate comma-separated values. Please have a look below at one example.

SELECT
    VendorId, STRING_AGG(FirstName,',') UsersName
FROM Users
WHERE VendorId != 9
GROUP BY VendorId

Answer 14

You need to create a variable that will hold your final result and select into it, like so.

Easiest Solution

DECLARE @char VARCHAR(MAX);

SELECT @char = COALESCE(@char + ', ' + [column], [column]) 
FROM [table];

PRINT @char;

Answer 15

In SQL Server vNext this will be built in with the STRING_AGG function. Read more about it in STRING_AGG (Transact-SQL).

Answer 16

This worked for me (SQL Server 2016):

SELECT CarNamesString = STUFF((
         SELECT ',' + [Name]
            FROM tbl_cars
            FOR XML PATH('')
         ), 1, 1, '')

Here is the source: https://www.mytecbits.com/

And a solution for MySQL (since this page show up in Google for MySQL):

SELECT [Name],
       GROUP_CONCAT(DISTINCT [Name]  SEPARATOR ',')
       FROM tbl_cars

From MySQL documentation.

Answer 17

A ready-to-use solution, with no extra commas:

select substring(
        (select ', '+Name AS 'data()' from Names for xml path(''))
       ,3, 255) as "MyList"

An empty list will result in NULL value. Usually you will insert the list into a table column or program variable: adjust the 255 max length to your need.

(Diwakar and Jens Frandsen provided good answers, but need improvement.)

Answer 18

Using XML helped me in getting rows separated with commas. For the extra comma we can use the replace function of SQL Server. Instead of adding a comma, use of the AS 'data()' will concatenate the rows with spaces, which later can be replaced with commas as the syntax written below.

REPLACE(
        (select FName AS 'data()'  from NameList  for xml path(''))
         , ' ', ', ') 

Answer 19

SELECT STUFF((SELECT ', ' + name FROM [table] FOR XML PATH('')), 1, 2, '')

Here's a sample:

DECLARE @t TABLE (name VARCHAR(10))
INSERT INTO @t VALUES ('Peter'), ('Paul'), ('Mary')
SELECT STUFF((SELECT ', ' + name FROM @t FOR XML PATH('')), 1, 2, '')
--Peter, Paul, Mary

Answer 20

With the other answers, the person reading the answer must be aware of a specific domain table such as vehicle or student. The table must be created and populated with data to test a solution.

Below is an example that uses SQL Server "Information_Schema.Columns" table. By using this solution, no tables need to be created or data added. This example creates a comma separated list of column names for all tables in the database.

SELECT
    Table_Name
    ,STUFF((
        SELECT ',' + Column_Name
        FROM INFORMATION_SCHEMA.Columns Columns
        WHERE Tables.Table_Name = Columns.Table_Name
        ORDER BY Column_Name
        FOR XML PATH ('')), 1, 1, ''
    )Columns
FROM INFORMATION_SCHEMA.Columns Tables
GROUP BY TABLE_NAME 

Answer 21

On top of Chris Shaffer's answer:

If your data may get repeated, such as

Tom
Ali
John
Ali
Tom
Mike

Instead of having Tom,Ali,John,Ali,Tom,Mike

You can use DISTINCT to avoid duplicates and get Tom,Ali,John,Mike:

DECLARE @Names VARCHAR(8000)
SELECT DISTINCT @Names = COALESCE(@Names + ',', '') + Name
FROM People
WHERE Name IS NOT NULL
SELECT @Names

Answer 22

MySQL complete example:

We have users who can have much data and we want to have an output, where we can see all users' data in a list:

Result:

___________________________
| id   |  rowList         |
|-------------------------|
| 0    | 6, 9             |
| 1    | 1,2,3,4,5,7,8,1  |
|_________________________|

Table Setup:

CREATE TABLE `Data` (
  `id` int(11) NOT NULL,
  `user_id` int(11) NOT NULL
) ENGINE=InnoDB AUTO_INCREMENT=11 DEFAULT CHARSET=latin1;


INSERT INTO `Data` (`id`, `user_id`) VALUES
(1, 1),
(2, 1),
(3, 1),
(4, 1),
(5, 1),
(6, 0),
(7, 1),
(8, 1),
(9, 0),
(10, 1);


CREATE TABLE `User` (
  `id` int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;


INSERT INTO `User` (`id`) VALUES
(0),
(1);

Query:

SELECT User.id, GROUP_CONCAT(Data.id ORDER BY Data.id) AS rowList FROM User LEFT JOIN Data ON User.id = Data.user_id GROUP BY User.id

Answer 23

DECLARE @Names VARCHAR(8000)
SELECT @name = ''
SELECT @Names = @Names + ',' + Names FROM People
SELECT SUBSTRING(2, @Names, 7998)

This puts the stray comma at the beginning.

However, if you need other columns, or to CSV a child table you need to wrap this in a scalar user defined field (UDF).

You can use XML path as a correlated subquery in the SELECT clause too (but I'd have to wait until I go back to work because Google doesn't do work stuff at home :-)

Answer 24

To avoid null values you can use CONCAT()

DECLARE @names VARCHAR(500)
SELECT @names = CONCAT(@names, ' ', name) 
FROM Names
select @names

Answer 25

I really liked elegancy of Dana's answer and just wanted to make it complete.

DECLARE @names VARCHAR(MAX)
SET @names = ''

SELECT @names = @names + ', ' + Name FROM Names

-- Deleting last two symbols (', ')
SET @sSql = LEFT(@sSql, LEN(@sSql) - 1)

Answer 26

This answer will require some privilege on the server to work.

Assemblies are a good option for you. There are a lot of sites that explain how to create it. The one I think is very well explained is this one.

If you want, I have already created the assembly, and it is possible to download the DLL file here.

Once you have downloaded it, you will need to run the following script in your SQL Server:

EXEC sp_configure 'show advanced options', 1
RECONFIGURE;
EXEC sp_configure 'clr strict security', 1;
RECONFIGURE;

CREATE Assembly concat_assembly
   AUTHORIZATION dbo
   FROM '<PATH TO Concat.dll IN SERVER>'
   WITH PERMISSION_SET = SAFE;
GO

CREATE AGGREGATE dbo.concat (

    @Value NVARCHAR(MAX)
  , @Delimiter NVARCHAR(4000)

) RETURNS NVARCHAR(MAX)
EXTERNAL Name concat_assembly.[Concat.Concat];
GO

sp_configure 'clr enabled', 1;
RECONFIGURE

Observe that the path to assembly may be accessible to server. Since you have successfully done all the steps, you can use the function like:

SELECT dbo.Concat(field1, ',')
FROM Table1

---

Since SQL Server 2017 it is possible to use the STRING_AGG function.

Answer 27

For Oracle DBs, see this question: How can multiple rows be concatenated into one in Oracle without creating a stored procedure?

The best answer appears to be by @Emmanuel, using the built-in LISTAGG() function, available in Oracle 11g Release 2 and later.

SELECT question_id,
   LISTAGG(element_id, ',') WITHIN GROUP (ORDER BY element_id)
FROM YOUR_TABLE;
GROUP BY question_id

as @user762952 pointed out, and according to Oracle's documentation http://www.oracle-base.com/articles/misc/string-aggregation-techniques.php, the WM_CONCAT() function is also an option. It seems stable, but Oracle explicitly recommends against using it for any application SQL, so use at your own risk.

Other than that, you will have to write your own function; the Oracle document above has a guide on how to do that.

Answer 28

This can be useful too

create table #test (id int,name varchar(10))
--use separate inserts on older versions of SQL Server
insert into #test values (1,'Peter'), (1,'Paul'), (1,'Mary'), (2,'Alex'), (3,'Jack')

DECLARE @t VARCHAR(255)
SELECT @t = ISNULL(@t + ',' + name, name) FROM #test WHERE id = 1
select @t
drop table #test

returns

Peter,Paul,Mary

Answer 29

In Oracle, it is wm_concat. I believe this function is available in the 10g release and higher.

Answer 30

I usually use select like this to concatenate strings in SQL Server:

with lines as 
( 
  select 
    row_number() over(order by id) id, -- id is a line id
    line -- line of text.
  from
    source -- line source
), 
result_lines as 
( 
  select 
    id, 
    cast(line as nvarchar(max)) line 
  from 
    lines 
  where 
    id = 1 
  union all 
  select 
    l.id, 
    cast(r.line + N', ' + l.line as nvarchar(max))
  from 
    lines l 
    inner join 
    result_lines r 
    on 
      l.id = r.id + 1 
) 
select top 1 
  line
from
  result_lines
order by
  id desc

Answer 31

If you want to deal with nulls you can do it by adding a where clause or add another COALESCE around the first one.

DECLARE @Names VARCHAR(8000) 
SELECT @Names = COALESCE(COALESCE(@Names + ', ', '') + Name, @Names) FROM People

Answer 32

SQL Server 2005 or later

CREATE TABLE dbo.Students
(
    StudentId INT
    , Name VARCHAR(50)
    , CONSTRAINT PK_Students PRIMARY KEY (StudentId)
);

CREATE TABLE dbo.Subjects
(
    SubjectId INT
    , Name VARCHAR(50)
    , CONSTRAINT PK_Subjects PRIMARY KEY (SubjectId)
);

CREATE TABLE dbo.Schedules
(
    StudentId INT
    , SubjectId INT
    , CONSTRAINT PK__Schedule PRIMARY KEY (StudentId, SubjectId)
    , CONSTRAINT FK_Schedule_Students FOREIGN KEY (StudentId) REFERENCES dbo.Students (StudentId)
    , CONSTRAINT FK_Schedule_Subjects FOREIGN KEY (SubjectId) REFERENCES dbo.Subjects (SubjectId)
);

INSERT dbo.Students (StudentId, Name) VALUES
    (1, 'Mary')
    , (2, 'John')
    , (3, 'Sam')
    , (4, 'Alaina')
    , (5, 'Edward')
;

INSERT dbo.Subjects (SubjectId, Name) VALUES
    (1, 'Physics')
    , (2, 'Geography')
    , (3, 'French')
    , (4, 'Gymnastics')
;

INSERT dbo.Schedules (StudentId, SubjectId) VALUES
    (1, 1)        --Mary, Physics
    , (2, 1)    --John, Physics
    , (3, 1)    --Sam, Physics
    , (4, 2)    --Alaina, Geography
    , (5, 2)    --Edward, Geography
;

SELECT
    sub.SubjectId
    , sub.Name AS [SubjectName]
    , ISNULL( x.Students, '') AS Students
FROM
    dbo.Subjects sub
    OUTER APPLY
    (
        SELECT
            CASE ROW_NUMBER() OVER (ORDER BY stu.Name) WHEN 1 THEN '' ELSE ', ' END
            + stu.Name
        FROM
            dbo.Students stu
            INNER JOIN dbo.Schedules sch
                ON stu.StudentId = sch.StudentId
        WHERE
            sch.SubjectId = sub.SubjectId
        ORDER BY
            stu.Name
        FOR XML PATH('')
    ) x (Students)
;

Answer 33

This method applies to the Teradata Aster database only as it uses its NPATH function.

Again, we have table Students

SubjectID       StudentName
----------      -------------
1               Mary
1               John
1               Sam
2               Alaina
2               Edward

Then with NPATH it is just single SELECT:

SELECT * FROM npath(
  ON Students
  PARTITION BY SubjectID
  ORDER BY StudentName
  MODE(nonoverlapping)
  PATTERN('A*')
  SYMBOLS(
    'true' as A
  )
  RESULT(
    FIRST(SubjectID of A) as SubjectID,
    ACCUMULATE(StudentName of A) as StudentName
  )
);

Result:

SubjectID       StudentName
----------      -------------
1               [John, Mary, Sam]
2               [Alaina, Edward]

Answer 34

Here is the complete solution to achieve this:

-- Table Creation
CREATE TABLE Tbl
( CustomerCode    VARCHAR(50)
, CustomerName    VARCHAR(50)
, Type VARCHAR(50)
,Items    VARCHAR(50)
)

insert into Tbl
SELECT 'C0001','Thomas','BREAKFAST','Milk'
union SELECT 'C0001','Thomas','BREAKFAST','Bread'
union SELECT 'C0001','Thomas','BREAKFAST','Egg'
union SELECT 'C0001','Thomas','LUNCH','Rice'
union SELECT 'C0001','Thomas','LUNCH','Fish Curry'
union SELECT 'C0001','Thomas','LUNCH','Lessy'
union SELECT 'C0002','JOSEPH','BREAKFAST','Bread'
union SELECT 'C0002','JOSEPH','BREAKFAST','Jam'
union SELECT 'C0002','JOSEPH','BREAKFAST','Tea'
union SELECT 'C0002','JOSEPH','Supper','Tea'
union SELECT 'C0002','JOSEPH','Brunch','Roti'

-- function creation
GO
CREATE  FUNCTION [dbo].[fn_GetItemsByType]
(   
    @CustomerCode VARCHAR(50)
    ,@Type VARCHAR(50)
)
RETURNS @ItemType TABLE  ( Items VARCHAR(5000) )
AS
BEGIN

        INSERT INTO @ItemType(Items)
    SELECT  STUFF((SELECT distinct ',' + [Items]
         FROM Tbl 
         WHERE CustomerCode = @CustomerCode
            AND Type=@Type
            FOR XML PATH(''))
        ,1,1,'') as  Items



    RETURN 
END

GO

-- fianl Query
DECLARE @cols AS NVARCHAR(MAX),
    @query  AS NVARCHAR(MAX)

select @cols = STUFF((SELECT distinct ',' + QUOTENAME(Type) 
                    from Tbl
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')

set @query = 'SELECT CustomerCode,CustomerName,' + @cols + '
             from 
             (
                select  
                    distinct CustomerCode
                    ,CustomerName
                    ,Type
                    ,F.Items
                    FROM Tbl T
                    CROSS APPLY [fn_GetItemsByType] (T.CustomerCode,T.Type) F
            ) x
            pivot 
            (
                max(Items)
                for Type in (' + @cols + ')
            ) p '

execute(@query) 

Answer 35

One way you could do it in SQL Server would be to return the table content as XML (for XML raw), convert the result to a string and then replace the tags with ", ".

Answer 36

Not that I have done any analysis on performance as my list had less than 10 items but I was amazed after looking through the 30 odd answers I still had a twist on a similar answer already given similar to using COALESCE for a single group list and didn't even have to set my variable (defaults to NULL anyhow) and it assumes all entries in my source data table are non blank:

DECLARE @MyList VARCHAR(1000), @Delimiter CHAR(2) = ', '
SELECT @MyList = CASE WHEN @MyList > '' THEN @MyList + @Delimiter ELSE '' END + FieldToConcatenate FROM MyData

I am sure COALESCE internally uses the same idea. Let’s hope Microsoft don't change this on me.

Answer 37

Below is a simple PL/SQL procedure to implement the given scenario using "basic loop" and "rownum"

Table definition

CREATE TABLE "NAMES" ("NAME" VARCHAR2(10 BYTE))) ;

Let's insert values into this table

INSERT INTO NAMES VALUES('PETER');
INSERT INTO NAMES VALUES('PAUL');
INSERT INTO NAMES VALUES('MARY');

Procedure starts from here

DECLARE 

MAXNUM INTEGER;
CNTR INTEGER := 1;
C_NAME NAMES.NAME%TYPE;
NSTR VARCHAR2(50);

BEGIN

SELECT MAX(ROWNUM) INTO MAXNUM FROM NAMES;

LOOP

SELECT NAME INTO  C_NAME FROM 
(SELECT ROWNUM RW, NAME FROM NAMES ) P WHERE P.RW = CNTR;

NSTR := NSTR ||','||C_NAME;
CNTR := CNTR + 1;
EXIT WHEN CNTR > MAXNUM;

END LOOP;

dbms_output.put_line(SUBSTR(NSTR,2));

END;

Result

PETER,PAUL,MARY

Answer 38

In PostgreSQL - array_agg

SELECT array_to_string(array_agg(DISTINCT rolname), ',') FROM pg_catalog.pg_roles;

Or STRING_AGG

SELECT STRING_AGG(rolname::text,',') FROM pg_catalog.pg_roles;

Answer 39

There are a couple of ways in Oracle:

    create table name
    (first_name varchar2(30));

    insert into name values ('Peter');
    insert into name values ('Paul');
    insert into name values ('Mary');

Solution is 1:

    select substr(max(sys_connect_by_path (first_name, ',')),2) from (select rownum r, first_name from name ) n start with r=1 connect by prior r+1=r
    o/p=> Peter,Paul,Mary

Solution is 2:

    select  rtrim(xmlagg (xmlelement (e, first_name || ',')).extract ('//text()'), ',') first_name from name
    o/p=> Peter,Paul,Mary

Answer 40

With the 'TABLE' type it is extremely easy. Let's imagine that your table is called Students and it has column name.

declare @rowsCount INT
declare @i INT = 1
declare @names varchar(max) = ''

DECLARE @MyTable TABLE
(
  Id int identity,
  Name varchar(500)
)
insert into @MyTable select name from Students
set @rowsCount = (select COUNT(Id) from @MyTable)

while @i < @rowsCount
begin
 set @names = @names + ', ' + (select name from @MyTable where Id = @i)
 set @i = @i + 1
end
select @names

This example was tested with SQL Server 2008 R2.

Answer 41

SELECT PageContent = Stuff(
    (   SELECT PageContent
        FROM dbo.InfoGuide
        WHERE CategoryId = @CategoryId
          AND SubCategoryId = @SubCategoryId
        for xml path(''), type
    ).value('.[1]','nvarchar(max)'),
    1, 1, '')
FROM dbo.InfoGuide info

Answer 42

Although it's too late, and already has many solutions. Here is simple solution for MySQL:

SELECT t1.id,
        GROUP_CONCAT(t1.id) ids
 FROM table t1 JOIN table t2 ON (t1.id = t2.id)
 GROUP BY t1.id

Answer 43

With a recursive query you can do it:

-- Create example table
CREATE TABLE tmptable (NAME VARCHAR(30)) ;

-- Insert example data
INSERT INTO tmptable VALUES('PETER');
INSERT INTO tmptable VALUES('PAUL');
INSERT INTO tmptable VALUES('MARY');

-- Recurse query
with tblwithrank as (
select * , row_number() over(order by name) rang , count(*) over() NbRow
from tmptable
),
tmpRecursive as (
select *, cast(name as varchar(2000)) as AllName from tblwithrank  where rang=1
union all
select f0.*,  cast(f0.name + ',' + f1.AllName as varchar(2000)) as AllName 
from tblwithrank f0 inner join tmpRecursive f1 on f0.rang=f1.rang +1 
)
select AllName from tmpRecursive
where rang=NbRow

Answer 44

Use this:

ISNULL(SUBSTRING(REPLACE((select ',' FName as 'data()' from NameList for xml path('')), ' ,',', '), 2, 300), '') 'MyList'

Where the "300" could be any width taking into account the maximum number of items you think will show up.

Answer 45

We can use RECUSRSIVITY, WITH CTE, union ALL as follows

declare @mytable as table(id int identity(1,1), str nvarchar(100))
insert into @mytable values('Peter'),('Paul'),('Mary')

declare @myresult as table(id int,str nvarchar(max),ind int, R# int)

;with cte as(select id,cast(str as nvarchar(100)) as str, cast(0 as int) ind from @mytable
union all
select t2.id,cast(t1.str+',' +t2.str as nvarchar(100)) ,t1.ind+1 from cte t1 inner join @mytable t2 on t2.id=t1.id+1)
insert into @myresult select *,row_number() over(order by ind) R# from cte

select top 1 str from @myresult order by R# desc

Answer 46

First of all you should declare a table variable and fill it with your table data and after that, with a WHILE loop, select row one by one and add its value to a nvarchar(max) variable.

    Go
    declare @temp table(
        title nvarchar(50)
    )
    insert into @temp(title)
    select p.Title from dbo.person p
    --
    declare @mainString nvarchar(max)
    set @mainString = '';
    --
    while ((select count(*) from @temp) != 0)
    begin
        declare @itemTitle nvarchar(50)
        set @itemTitle = (select top(1) t.Title from @temp t)
    
        if @mainString = ''
        begin
            set @mainString = @itemTitle
        end
        else
        begin
            set @mainString = concat(@mainString,',',@itemTitle)
        end
    
        delete top(1) from @temp
    
    end
    print @mainString

Answer 47

   declare @phone varchar(max)='' 
   select @phone=@phone + mobileno +',' from  members
   select @phone