SQLServerCentral / Article Discussions / Article Discussions by Author / Discuss content posted by Hugo Kornelis / MERGE with ANSI / Latest Posts

RE: MERGE with ANSI

sbamaty — Thu, 29 Dec 2011 15:15:56 GMT

My brain almost exploded..lol!! Pretty hard question. I actually have to open my book and read more about MERGE statement. I was under impression that this MERGE functionality came in SQL2008 only since I start using it in SQL2008 only. I didn't get lots of opportunities to play with newer functionality in 2005.One thing I would like to point out is that MERGE statement does allows BY SOURCE and BY TARGET in the statement. Here's the snippet of code where I use both:MERGE dbo.column_collection AS ccUSING dbo.staging_column_collection AS sccON ( scc.table_name = cc.table_name AND scc.database_name = cc.database_name AND scc.ordinal_position = cc.ordinal_position AND scc.record_status = cc.record_status AND scc.schema_name = cc.schema_name AND cc.record_status = 'A' AND scc.platform_type_code = cc.platform_type_code AND scc.database_name NOT LIKE '_broken%' )WHEN MATCHED AND cc.physical_column_name <> scc.physical_column_name OR cc.data_type <> scc.data_type OR cc.column_length <> scc.column_lengthTHEN UPDATE SET cc.physical_column_name = scc.physical_column_name , cc.column_name = scc.column_name , cc.data_type = scc.data_type , cc.column_length = scc.column_length WHEN NOT MATCHED BY TARGET THEN INSERT ( column_name , physical_column_name , data_type , column_length , column_definition , record_status, insert_date , table_name, database_name , ordinal_position , schema_name , platform_type_code ) VALUES ( scc.column_name , scc.physical_column_name , scc.data_type , scc.column_length , scc.column_definition , scc.record_status , scc.insert_date , scc.table_name , scc.database_name , scc.ordinal_position , schema_name , platform_type_code )WHEN NOT MATCHED BY SOURCE THEN UPDATE SET cc.record_status = 'D'

RE: MERGE with ANSI

Britt Cluff — Tue, 29 Nov 2011 06:17:18 GMT

Challenging question. Thanks for submitting.

RE: MERGE with ANSI

OzYbOi d(-_-)b — Mon, 28 Nov 2011 16:10:28 GMT

thanks Hugo!

RE: MERGE with ANSI

SQLRNNR — Mon, 28 Nov 2011 09:26:12 GMT

Thanks Hugo

RE: MERGE with ANSI

Revenant — Mon, 28 Nov 2011 09:18:22 GMT

I have unbfair advantage: MERGE is my daily bread. ;-)Thanks for this interesting question!

RE: MERGE with ANSI

Anipaul — Mon, 28 Nov 2011 00:08:34 GMT

A very tough question....

RE: MERGE with ANSI

Koen Verbeeck — Sun, 27 Nov 2011 23:27:52 GMT

Tough one, thanks.

RE: MERGE with ANSI

KWymore — Fri, 25 Nov 2011 11:57:37 GMT

Nice question Hugo, had to do some research before answering this one and I still was surprised that I got it right. I think my brain now hurts too much to get anything else done today. Happy Friday!

RE: MERGE with ANSI

L' Eomot Inversé — Fri, 25 Nov 2011 09:20:35 GMT

[quote][b]martin.whitton (11/25/2011)[/b][hr]The MERGE statement is only available in SQL Server 2008 and later.I don't think this has any bearing on the low percentage of people getting this right, though...![/quote]Actually the percentage doesn't seem too bad - up to now 12% got it right; that's a bit more than four times as many as would be expected if everyone ticked 4 boxes chosen at random from the seven boxes provided. There have been much worse responses to other questions.But I agree this one was pretty hard.

RE: MERGE with ANSI

L' Eomot Inversé — Fri, 25 Nov 2011 09:11:28 GMT

Good question and good explanation - and thanks especially for the link to a late draft of the SQL 2003 standard.It was a bit hard for a Friday question, just when people are getting ready to relax for the weekend (careless scheduling by Steve there, or did he do it on purpose?). I spent a long time racking my brain to try to remember which was the fourth box to tick - after I had ticked three boxes all the others seemed as if they ought to be left unticked; and then I clicked that only UPDATE was allowed in WHEN MATCHED, not DELETE, so as I had already ticked WHEN NOT MATCHED BY SOURCE I logically had to tick DELETE as my fourth choice. Definitely good excercise for the grey matter.

RE: MERGE with ANSI

Hugo Kornelis — Fri, 25 Nov 2011 03:20:08 GMT

Thanks, all, for the kind words! I am glad you all find my questions entertaining and informative.[quote][b]martin.whitton (11/25/2011)[/b][hr]The MERGE statement is only available in SQL Server 2008 and later.[/quote]Oops! :blush: Stupid mistake - sorry 'bout that![quote][b]Stewart "Arturius" Campbell (11/25/2011)[/b][hr]I think the main reason for the poor score rate is that the SQL ANSI:2003 definitions are not readily available.[/quote]I included a link to a freely available version (of a late draft, not the official final version) in the answer's explanation. When I first found this link, I immediately downloaded it to my computer for fear of it being removed. When I submitted the question, I had to use Google to re-find the link.As far as I know, there are no newer versions of the ANSI SQL standard that are freely available (unfortunately).By the way - after submitting this question, I found that most of the non-SQL:2003 stuff in MERGE was not added by Microsoft for SQL Server only, but is defined in SQL:2008. So I was very glad that I included the version of the standard in the question! :-D

RE: MERGE with ANSI

martin.whitton — Fri, 25 Nov 2011 02:41:53 GMT

[quote]I came across this interesting and helpful [url=http://sqlblog.com/blogs/hugo_kornelis/archive/2008/03/10/lets-deprecate-update-from.aspx]blog post[/url] by one [i]Hugo Kornelis[/i] :-).Hence a double thank you to Hugo for an excellent QotD on MERGE following the ANSI standard, and for sharing your extensive knowledge with everybody on the web.l[/quote]Thank you Michael (and Hugo!) for that very useful link.Despite my minor bit of pedantry about the SQL versions, I second your thanks to Hugo - I always read his contributions with interest and often learn from them. :-)

RE: MERGE with ANSI

adb2303 — Fri, 25 Nov 2011 02:37:20 GMT

My brain hurts...

RE: MERGE with ANSI

michael.kaufmann — Fri, 25 Nov 2011 02:20:43 GMT

[quote][b]Stewart "Arturius" Campbell (11/25/2011)[/b][hr]This was quite a tough one.Learned a fair bit about the origin of the MERGE statement from this.[/quote]I definitely second this.Some may argue it's cheating to do some reading (researching) prior to answering the QotD, but I came across this interesting and helpful [url=http://sqlblog.com/blogs/hugo_kornelis/archive/2008/03/10/lets-deprecate-update-from.aspx]blog post[/url] by one [i]Hugo Kornelis[/i] :-).Hence a double thank you to Hugo for an excellent QotD on MERGE following the ANSI standard, and for sharing your extensive knowledge with everybody on the web.You all have a great weekend,Michael

RE: MERGE with ANSI

Stewart "Arturius" Campbell — Fri, 25 Nov 2011 01:54:41 GMT

This was quite a tough one.Learned a fair bit about the origin of the MERGE statement from this.Took a fair amount of thinking and digging to get it, though.I think the main reason for the poor score rate is that the SQL ANSI:2003 definitions are not readily available.

RE: MERGE with ANSI

martin.whitton — Fri, 25 Nov 2011 01:39:40 GMT

[quote]Given the MERGE statement below, which is completely correct for SQL Server 2005 and later[/quote]The MERGE statement is only available in SQL Server 2008 and later.I don't think this has any bearing on the low percentage of people getting this right, though...!

MERGE with ANSI

Hugo Kornelis — Thu, 24 Nov 2011 23:31:04 GMT

Comments posted to this topic are about the item [B]MERGE with ANSI[/B]