One of the most common questions I receive in email is how to group multiple columns data in comma separate values in a single row grouping by another column.
I have previously blogged about it in following two blog posts. However, both aren’t addressing the following exact problem.
- Comma Separated Values (CSV) from Table Column
- Comma Separated Values (CSV) from Table Column – Part 2
The question comes in many different formats, but in following image I am demonstrating the same question in simple words. This is the most popular question on my Facebook page as well. (Example)
Here is the sample script to build the sample dataset.
CREATE TABLE TestTable (ID INT, Col VARCHAR(4)) GO INSERT INTO TestTable (ID, Col) SELECT 1, 'A' UNION ALL SELECT 1, 'B' UNION ALL SELECT 1, 'C' UNION ALL SELECT 2, 'A' UNION ALL SELECT 2, 'B' UNION ALL SELECT 2, 'C' UNION ALL SELECT 2, 'D' UNION ALL SELECT 2, 'E' GO SELECT * FROM TestTable GO
Here is the solution which will build an answer to the above question.
-- Get CSV values SELECT t.ID, STUFF( (SELECT ',' + s.Col FROM TestTable s WHERE s.ID = t.ID FOR XML PATH('')),1,1,'') AS CSV FROM TestTable AS t GROUP BY t.ID GO
I hope this is an easy solution. I am going to point to this blog post in the future for all the similar questions.
Final Clean Up Act
-- Clean up DROP TABLE TestTable GO
Here is the question back to you –
Is there any better way to write above script? Please leave a comment and I will write a separate blog post with due credit.
Reference:Â Pinal Dave (https://blog.sqlauthority.com)
56 Comments. Leave new
currentData ExceptedData
1 1
1 2
1 3
1 4
2 6
3 9
5 14
6 20
2 22
1 23
1 24
1 25
1 26
1 27
adding row data that is present in excepted data.
hi,
I have total of 5 columns
id, Col1, Col2, Col3, Col4
1, a, 1, x, r
1, b, 2, y, s
Expected result:
id, Col1, Col2, Col3, Col4
1, ‘a,b’, ‘1,2’, ‘x,y’, ‘r,s’
Any suggested, as i dont want to use multi[le ‘for xml’ and table scans
Please use STRING_AGG bulid in function.but this function only support in Sql server 2017
it’s query slow when record will greater than 10000
The STUFF becomes slower when we are dealing with tables that have million+ records. My source table has 100 million records and the query to group and have the fields comma separated using stuff is running for more than 16 hours – I stopped it as it didn’t seem like a viable option. Any idea on how we achieve this with sql 2016 or below?
Same here. My table has 100 million + records and it’s never ending. Did you find any other solution? Cannot use string concat as my clients sql is 2016