A chairde - morning!

morning

@bbaird Re. Van Morrison - was never a fan - bit before my time... was into Lizzy and SLF and then after that I was into Celtic rock (Planxty, Moving Hearts, Horseslips, Hot House Flowers, In Tuath Nua and others... what I like about these bands is that they don't sound like they could be from San Diego or London or Sydney like so many Irish bands (not looking at U2 at all!... :-) ), so as to what he did before, what he's doing now and how they might be different,

I can't really comment -he was just never on my raday. I'm not a huge music listener - I frequently prefer either news or documentaries (economics, current affairs, politics, science, nature, history, geography...)...

While driving, I find classical music soothing...

U2 changed a lot over the years

And not for the better...

No

@Vérace FYI the OP had already changed key to keyy (in revision 3). You seem to have overwritten that.

Not that that is the biggest problem with the post.

I started to lose hope when the original tags sql-server and mysql were 'corrected' to sql-server only, then some time later to mysql only.

Nope - thought that was a typo... just trying to show them what they should be doing... and this time, I did tell them what I had done - they can always reverse the changes. It'll probably get closed anyway, but give the OP time to respond - yeah, tags - it's obviously MySQL - the dreaded backtick reared its ugly head...

@Vérace What do you mean "nope"? Also, it was only obvious it was MySQL after the backticks were introduced - not the case originally or when mysql was removed.

The only changes in revision 3 were to replace all occurrences of key with keyy

"Nope" means that I didn't inadvertently overwrite keyy - thought it was a typo - so I rewrote using t_key and v_key... I edited when there were backticks - was going to remove SQL Server but that had been done...

I see.

rain

new definition of cross join

and you all wonder why I dislike chatty comments

@ypercubeᵀᴹ is that an unexpected occurrence?

I recall you saying it had been hot recently

It was and still is hot, in Greece. I am stuck in the Rainy Land ;)

Aha!

My wife's family are in England. They were complaining that it had been cold recently, not so much about rain.

Not great here in Ireland either... much of our weather has been coming from the east - hence also cold...

I have a friend in Germany. They are expecting close to 30C tomorrow.

Perhaps that will make its way westward.

Noticed the CROSS JOIN thing also... didn't worry too much about. it

it's not a cross join though

I know - it's a CROSS JOIN on a key! :-) LOL!

ooo the question has been edited

let's see if it makes any sense now

seems answerable now

Still not all corner cases covered. Any answer would have to do some speculation.

Unusual on this site. Our questions are normally perfectly specified works of art.

haha, yeah!

It's probably good enough now that I would no longer vote to close it.

My guess is they want UNION JOIN or something along those lines.

(disjoined union), not sure of the math term in english

Oh I was wondering why my query wouldn't work then noticed they changed one data item.

@Vérace It looks like you're ready to add an answer?

Or are you still trying to clarify the question?

Nope - this time, nope means that I stil can't see an answer there... How do I JOIN/ANTI-JOIN [ho, phi and duc] and [itsme and white] ? Surely not a [W|w]hite causing grief again? :-)

I thought they were after:

dbfiddle.uk/…

But that returns two rows.

Yeah, I was reading the same. An antijoin (or two because they want not matching data from either table) and then some kind of pivot.

dbfiddle.uk/…

Very contrived though... i'd prefer to have a clear definiton from the OP!

Well exactly. The question doesn't mention inequality at all.

Goodness only knows. I don't think they're sure themselves.

I bet some crucial application depends on all this though.

Maybe retail or a mobile phone operator.

@PaulWhite true, we hadn't much rain lately. I guess I got used to it and having to drive on rain today got me by surprise. Or maybe because I was listening to Greek radio and how they are opening beaches ;)

Well one can still go to the beach when it is cold and raining

Might not be as much fun I grant you

That 's a recipe for depression!

Couldn't have that in the UK!

Anyway, give it two weeks and it'll be >35C in England

It might only last a day and a half, but still

They are already wearing shorts...

Only a matter of time before the traditional pictures of sunburnt bodies on Brighton beach

FULL JOIN - WHERE x IS NOT NULL - GROUP BY would answer the question, for the limited supplied case.

And then we'd get a comment from the OP: yeah, but...

I've lost interest now

I'll reopen it if someone else votes to do so first, with an intent to answer

And of course we have a random upvote. Yeah that question deserves 10 rep.

@PaulWhite Not retail or mobile phone operator - must be an airline - probably a vital flight control system in an aircraft...

Probably

Do airlines use MySQL?

I know some of them use Windows... <gulp..> :-) IMHO, we'd be lucky if they used MySQL - the db that I used when I worked in the area as some sort of Pervasive Btrieve thingy that had unreal data structures. For missiion critical tasks, people used Excel in preference to trusting the database... MySQL isn't quite that bad... but I suppose it depends on the implementation - a good impementation on Notepad as a storage engine would be better than a bad one on MySQL/SQL Server/Oracle...

wow that is ancient

My job was tranferring data from it to a SQL Server db to provide a flight pay system (which the original was meant to do...)...

Well I hope it rejected all nulls

Didn't have any - I just had an entry per flight per crew member onboard - if there was no crew member on the flight, no need for a record - no need for NULLs...

yeah it was a joke

@PaulWhite I've heard of a US/NATO demonstratuon of a completely remotely controlled ship that was a complete success, somewhere in the 2000, give or take a few years. OS: Windows NT.

Complete success except of the 3-4 minutes that needed reboot after a blue screen of death.

🤣

Or was it black screen in NT? I can't remember.

en.m.wikipedia.org/wiki/Blue_screen_of_death

heh, I wasn't sure to what typo you wree referring to!

@verace we had some discussion related to assertions the other day. Here's a link about "constraint" triggers, somewhat related: triggers-to-enforce-constraints

the writer of the post is active on our site, too: dba.stackexchange.com/users/176905/laurenz-albe