Sql Merging multiple records into one record

Question

I have table with two columns user_id and tags.

  user_id    tags
    1    
    1    
    1    

        

Answer 1

duplicate of https://stackoverflow.com/questions/16218616/sql-marching-values-in-column-a-with-more-than-1-value-in-column-b/16218678#16218678

select user_id, group_concat(tags separator ',')
from t
group by user_id

Answer 2

Try this one -:

SELECT t2.userid,
stuff((
SELECT ', ' + t1.tags
FROM table_name as t1
where t1.userid = t2.userid
FOR XML PATH('')
), 1, 2, '')
FROM table_name as t2
GROUP BY t2.userid

I hope this helps you out.

Check the example -: http://www.sqlfiddle.com/#!3/85c89/6

Answer 3

You should look into the GROUP_CONCAT function in mysql.A good example is here

In your case it would be something like:

SELECT user_id, GROUP_CONCAT(tags) FROM tablename GROUP BY user_id