upgrade MS SQL from MSSQL 2012 SP4 to MSSQL 2014 SP3-CU4 .

Why do you want to upgrade to an older version?
You have to purchase to licence of SQL Server then you can upgrade to the newest.

I would upgrade to SQL 2016 or 2017 instead of just 2014 as this will give longer support life aside other benefits.
Before upgraded please run the DMA as described here: https://docs.microsoft.com/en-us/sql/database-engine/install-windows/prepare-for-upgrade-by-running-data-migration-assistant?view=sql-server-ver15
Most important thing is to take a FULL backups of existing DB's just prior to the upgrade and KEEP THEM SAFE on some separate storage just in case.
Other than that you should be good to upgrade in place your SQL server as noted here: https://docs.microsoft.com/en-us/sql/database-engine/install-windows/upgrade-sql-server?view=sql-server-ver15

Máté Farkas

I am referreing to MSSQL 2012 SP4 to MSSQL 2014 SP3-CU4 .

lcohan,

I would upgrade to SQL 2016 or 2017 instead of just 2014 as this will give longer support life aside other benefits.

sure, but step by step !

Most important thing is to take a FULL backups of existing DB's just prior to the upgrade and KEEP THEM SAFE on some separate storage just in case.

Sure ! of course ! you are referring to in place upgrade?

Before upgraded please run the DMA as described here:

but we are going to do verision upgrade, still need this ?

Other than that you should be good to upgrade in place your SQL server as noted here

this is for MSSQL 2012 SP4 to MSSQL 2014 SP3-CU4 ? can't upgrade directly from MSSQL 2012 SP4 to MSSQL 2014 SP3-CU4 ?
is it possible to rollback ? how ? any URL for it ?

"Sure ! of course ! you are referring to in place upgrade?" - in particular if you perform an in-place upgrade as you never mentioned migration/upgrade...
"but we are going to do verision upgrade, still need this ?" - of course as you will install the toll and just run the "Assessment" from SQL to SQL so you can see if there anr any breaking changes - unlikely if you just go from 2012 to 2014 but again..why just get stuck on "MSSQL 2014 SP3-CU4"??


"this is for MSSQL 2012 SP4 to MSSQL 2014 SP3-CU4 ? can't upgrade directly from MSSQL 2012 SP4 to MSSQL 2014 SP3-CU4 ?"
you actually "can upgrade directly" if you build a new SQL 2014 SP3-CU4 (but again why stuc on this old version?) then perform the "upgrade" via a backup existing DB's on 2012 SP4 then restore those backups to 2014 SP3-CU4 and the DB level upgrade will be implicitly done.

"is it possible to rollback ? how ? any URL for it ?" - the only rollback (going back to 2012) I'm aware of would be to restore from those SQL 2012 backups so you must test your apps well and have a GO-NOGO decision BEFORE running full production on the SQL 2014 SP3-CU4

nlikely if you just go from 2012 to 2014 but again..

no change from 2012 to 2014?

(but again why stuc on this old version?)

business requiremnet

you actually "can upgrade directly" if you build a new SQL 2014 SP3-CU4 (but again why stuc on this old version?)

if both server in separate machijne ?

you actually "can upgrade directly" if you build a new SQL 2014 SP3-CU4

so if on the same machine we can't direct upgrade?

the only rollback (going back to 2012) I'm aware of would be to restore from those SQL 2012 backups

binary has to be reinstall on other machine then restore with old backup on that separate SQL 2012 box ?

Do you have a server(machine) with multiple instances running SQL 2012 and SQL 2014?

only one instance with SQL 2012 with SP4!

so just upgrade from MSSQL 2012 SP4 to MSSQL 2014 SP3-CU4 on the same box of course ! any problem will happen ? any know issue ?

No "problem will happen " during the upgrade however it is obvious that any fixes starting with SQL Server 2014 SP2 Cumulative Update 5 could become a potential issues in your SQL 2014 SP2+CU4 as they are not included and you can see  the full list at link below:
https://www.sqlskills.com/blogs/glenn/performance-and-stability-related-fixes-in-post-sql-server-2014-sp2-builds/

Just make sure you have all the database FULL backups taken/saved prior to the upgrade in case you will need to rollback to SQL 2012 SP4.

Just make sure you have all the database FULL backups taken/saved prior to the upgrade in case you will need to rollback to SQL 2012 SP4.

sure , but it needs to reinstall of SQL server 2012 and SP4 right ? these kind of big version can't simple click uninstall .

SQL Server 2014 SP2 Cumulative Update 5 could become a potential issues in your SQL 2014 SP2+CU4 as they are not included

sorry, you mean after SP2 CU5 a lot of fix has issue ? but I am going to upgrade to SP3, big trouble then ?

Of course you will have to fully uninstall SQL 2014 and install again SQL 2012+SP3 in case you need to go back to older version.

sorry, you mean after SP2 CU5 a lot of fix has issue ? but I am going to upgrade to SP3, big trouble then ?

You are saying from the beginning "...upgrading MSSQL 2012 SP4 to MSSQL 2014 SP3-CU4..." so why now "I am going to upgrade to SP3"?
Aside that whether you upgrade to SQL 2014 SP3 only and stop there OR to SQL 2014 SP3-CU4 as you mentioned above what I'm trying to say is that ANY fixes included post build number/version of SQL you will run are obviously not applied to your environment therefor you may have potential issues and NOT that you will have big trouble.

ok

tks.

we need to test it anyway.