Can someone help me how to use join in these tables I created?

It’s a drilling and blasting company…

So describe it with as many details as you can

So, the company has a several depts .. i.e , Bs strategy, Finance , Store, HR, Architecture Design, Construction, Mechanical , Drilling,Blasting and support staff …

So the tables above are what i have set up as the db so far ..

Employees are of different levels depending on who they report to

Does a single employee have ability of belong to a few departments?

There is something called mysqlbinlog –flashback for innodb tables in mysql 8.0 that can be used to recover the data provided you at least have binary logs. It’s a tideous task though

They belong to just one department and always report to just one person but there’re unique situations where guys from the drilling dept would assist in work in the construction depts ..

And what is the general issue your database should solve?

Well my database should be able to solve the issues of reporting .. who reports to who .. but at the moment I’m been told to simplify it .. it has to much duplications ..

What duplication?

For what purpose the same?

Why do you need the same if you already have one?

So what do you need?

Which elements exactly?

There are strict rules of its behavior in different situations. You’d better to read documentation first, then ask about things keeped unclear for you.

Hi guys. Can enybody give me an advise? Where from can I upload testing models of MYSQL base, describing employe or staff, or something like?

It throws an error, table already exists

And then, probably, duplicated key

hello, that is the expected answer

this is what i have done

anyone can help me with this matter

This is not even close to what’s needed.

Ah that great I can do that

So what is the correct way

it is too long to explain in chat.

You must extract YEAR , use windowing functions to group records by year, range records by whatever defines this f… rating (it is NOT stated in the task, BTW), and limit each group by only one record.

As ilia said, Maybe you can first get every year and country

Then add a subquery to get the top vendor “where” matches that year and country, perhaps using order and limit

Finally, union that with the same query, but change the limit to show the second one

Order as desired at the end

Windowing functions is only supported since version 8

Can someone help me how to use join in these tables I created?

I have 3 tables – product, invoice, invoice_item.
I have to retrieve product_name from product table and issued, due, paid from invoice table.

Product table and invoice table are linked to the third table(invoice_item)

In lines 23 and 24

hi, fix the gaps
select product_name, isued, due, paid
from product
join invoice_item on product_id = product.id
join invoice on invoice.id = invoice_id

Thanks Rodrigo. Works perfectly.

^_^