Concatenating records in a single column without looping?

Question

I have a table with 1 column of varchar values. I am looking for a way to concatenate those values into a single value without a loop, if possible. If a loop is the most e

Answer 1

Probably dated now but check out Adam Machanic's post on the topic.

And this one is certainly dated; I wrote it in 2004.

Why do I prefer a function over "keeping it inside a SQL query"? Because you'll probably have to do this more than once. Why not encapsulate that code into a single module instead of repeating it all over the place?

Answer 2

try this:

DECLARE @YourTable table (Col1 int)
INSERT INTO @YourTable VALUES (1)
INSERT INTO @YourTable VALUES (2)
INSERT INTO @YourTable VALUES (30)
INSERT INTO @YourTable VALUES (400)
INSERT INTO @YourTable VALUES (12)
INSERT INTO @YourTable VALUES (46454)

SELECT
    STUFF(
             (
                  SELECT
                      ', ' + cast(Col1 as varchar(30))
                      FROM @YourTable
                      WHERE Col1<=400
                      ORDER BY Col1
                      FOR XML PATH('')
             ), 1, 2, ''
         )

OUTPUT:

-------------------
1, 2, 12, 30, 400

(1 row(s) affected)

Answer 3

If it is MySQL, you can use GROUP_CONCAT

SELECT a, GROUP_CONCAT(b SEPARATOR ',') FROM table GROUP BY a;

Answer 4

I just tackled a problem like this and looping took forever. So, I concantenated the values in the presentation medium (in this case Crystal Reports) and it was very fast.

Just an idea.

Answer 5

declare @concat varchar(max) set @concat = ''

select @concat = @concat + col1 + ',' from tablename1