Why You May Need More Than FOR XML PATH(”)

XML – both easy, easy, lemon easy and difficult, difficult, lemon difficult…

Working on a blog post and I came up against a problem that I had heard of before but did not spend much brain-CPU power against.

know I’m going to run into this again so let’s document this for future me. Oh he’s going to appreciate this so much!

Commas are all the rage nowadays:

There are a fair number of questions nowadays about returning data from a database in a comma separated string. Sure the application should probably do that but hey, database servers are expensive, why not get some bang for your bucks!

Done!-ish…

SQL Server 2017 has this lovely function called STRING_AGG()

Pop in your column and your separator and it takes care of it for you!

…wait not everyone has SQL Server 2017 yet?

…wait don’t have SQL Server 2017 yet? Oh, I should really fix that…

Pre-SQL Server 2017:

So what can we do if we are not on SQL Server 2017? Take the advice that I was given for most of my life and STUFF it!

The STUFFing:

Our playground:

USE tempdb;

-- Test table
SELECT dt.comments
FROM ( VALUES ( 'XML is the bomb!'),
              ( '& JSON is cool too...')
     ) AS dt (comments);
TestTable
testing stuff…

 

Plain Old STUFFing:

I’m not the biggest fan of stuffing if I’m honest…tastes like dirt to me but hey, it works in 99% of situations…

SELECT STUFF((SELECT ', ' + dt.comments
              FROM ( VALUES ( 'XML is the bomb!'),
                            ( '& JSON is cool too...')
                   ) AS dt (comments)
              FOR XML PATH('')
             ), 1, 1, '') AS CommentsEnXML;

 

StandardWay
…that’s…that’s not what I said!

Bacon Sausage STUFFing however:

So…SQL Server is trying to be too helpful. What do we do? I normally turn to the SQL community and people like Rob Farley ( blog | twitter ), who has a lovely post about this.

So let’s try it out.

SELECT STUFF((SELECT ', ' + dt.comments
              FROM ( VALUES ( 'XML is the bomb!'),
                            ( '& JSON is cool too...')
                   ) AS dt (comments)
              FOR XML PATH(''),
              TYPE).value('.', 'varchar(max)'
             ), 1, 1, '') AS CommentsEnXML;

 

BetterWay
That exclamation mark is annoying me 😡

I just eat the turkey around the STUFFing:

Little hiccup in preparing for my next post. Thankfully I learn from my mistakes and failures (there’d be no help for me otherwise!).

I’ll leave this post with a quote from the blog of the main man himself:

It’s a habit I need to use more often.

Yeah, me too Rob, me too…