beliefer opened a new pull request #27440:
URL: https://github.com/apache/spark/pull/27440
### What changes were proposed in this pull request?
The `NTH_VALUE` function is an ANSI SQL.
For examples:
```
CREATE TEMPORARY TABLE empsalary (
depname varchar,
empno bigint,
salary int,
enroll_date date
);
INSERT INTO empsalary VALUES
('develop', 10, 5200, '2007-08-01'),
('sales', 1, 5000, '2006-10-01'),
('personnel', 5, 3500, '2007-12-10'),
('sales', 4, 4800, '2007-08-08'),
('personnel', 2, 3900, '2006-12-23'),
('develop', 7, 4200, '2008-01-01'),
('develop', 9, 4500, '2008-01-01'),
('sales', 3, 4800, '2007-08-01'),
('develop', 8, 6000, '2006-10-01'),
('develop', 11, 5200, '2007-08-15');
select first_value(salary) over(order by salary range between 1000 preceding
and 1000 following),
lead(salary) over(order by salary range between 1000 preceding and 1000
following),
nth_value(salary, 1) over(order by salary range between 1000 preceding
and 1000 following),
salary from empsalary;
first_value | lead | nth_value | salary
-------------+------+-----------+--------
3500 | 3900 | 3500 | 3500
3500 | 4200 | 3500 | 3900
3500 | 4500 | 3500 | 4200
3500 | 4800 | 3500 | 4500
3900 | 4800 | 3900 | 4800
3900 | 5000 | 3900 | 4800
4200 | 5200 | 4200 | 5000
4200 | 5200 | 4200 | 5200
4200 | 6000 | 4200 | 5200
5000 | | 5000 | 6000
(10 rows)
```
There are some mainstream database support the syntax.
**PostgreSQL:**
https://www.postgresql.org/docs/8.4/functions-window.html
**Vertica:**
https://www.vertica.com/docs/9.2.x/HTML/Content/Authoring/SQLReferenceManual/Functions/Analytic/NTH_VALUEAnalytic.htm?tocpath=SQL%20Reference%20Manual%7CSQL%20Functions%7CAnalytic%20Functions%7C_____23
**Oracle:**
https://docs.oracle.com/en/database/oracle/oracle-database/19/sqlrf/NTH_VALUE.html#GUID-F8A0E88C-67E5-4AA6-9515-95D03A7F9EA0
**Redshift**
https://docs.aws.amazon.com/redshift/latest/dg/r_WF_NTH.html
**Presto**
https://prestodb.io/docs/current/functions/window.html
### Why are the changes needed?
The `NTH_VALUE` function is an ANSI SQL.
The `NTH_VALUE` function is very useful.
### Does this PR introduce any user-facing change?
No
### How was this patch tested?
Exists and new UT.
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