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]).

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; 

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 

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 [email protected] 2 NULL 3 [email protected], [email protected] 

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

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 

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 

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; 

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.

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) 

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 

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 

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 

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/

For newer SQL versions (finally implemented)

SELECT STRING_AGG(Name, ', ') AS CarNames FROM tbl_TypeCar; 

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.

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; 

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

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.)

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('')) , ' ', ', ') 

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 

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 

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 

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 

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) 

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 :-)

To avoid null values you can use CONCAT()

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

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.

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 

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 

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

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.