Add SQL examples to window functions: `nth_value`, etc

[jonathanc-n]

Is your feature request related to a problem or challenge?

Mentioned in #13395

Describe the solution you'd like

Add SQL examples to the window functions (nth_value, cumedist, etc.) through the dynamically created docs, an example of it can be found here: #13390

The window function docs are here: https://datafusion.apache.org/user-guide/sql/window_functions.html

The goal is to have SQL examples for each function

Describe alternatives you've considered

No response

Additional context

No response

[jonathanc-n]

@alamb This can also be given a good first issue label.

[alamb]

Thanks @jonathanc-n -- here are some notes to help anyone who wants to help with this:

What I normaly do is fire up datafusion-cli and copy/paste the result of the query into the code

So for example, to test cume_dist

https://datafusion.apache.org/user-guide/sql/window_functions.html#cume-dist

I would do

> SELECT x, cume_dist() OVER (ORDER BY y) as cume_dist FROM VALUES (1,20), (2, 10), (3,30) t(x,y);
+---+--------------------+
| x | cume_dist          |
+---+--------------------+
| 2 | 0.3333333333333333 |
| 1 | 0.6666666666666666 |
| 3 | 1.0                |
+---+--------------------+
3 row(s) fetched.
Elapsed 0.002 seconds.

BTW the syntax

VALUES (1,20), (2, 10), (3,30) t(x,y);

Basically creates a temporary table named t with columns x and y

[sageraven1]

take

[rawwar]

@sageraven1 , Are you still working on this? I see that PR was marked as stale and got closed. If you aren't working on this, I would like to pick this up and complete it.

CC: @alamb

[alamb]

@sageraven1 , Are you still working on this? I see that PR was marked as stale and got closed. If you aren't working on this, I would like to pick this up and complete it.

That is great! thanks @rawwar

It appears the functions still do not have examples:
https://datafusion.apache.org/user-guide/sql/window_functions.html#first-value

[sageraven1]

@sageraven1 , Are you still working on this? I see that PR was marked as stale and got closed. If you aren't working on this, I would like to pick this up and complete it.

CC: @alamb

Yes, please feel free to take this! Apologies it got stale, life happened.

[Adez017]

Hi @alamb , i am also interested in this ? can I do that ?

[alamb]

Hi @alamb , i am also interested in this ? can I do that ?

Absolutely -- see https://datafusion.apache.org/contributor-guide/index.html#open-contribution-and-assigning-tickets for details on ticket assignments in general