# name: test/sql/window/test_nthvalue.test
# description: Most basic window function
# group: [window]

statement ok
SET default_null_order='nulls_first';

statement ok
PRAGMA enable_verification

statement ok
CREATE TABLE empsalary (depname varchar, empno bigint, salary int, enroll_date date);

statement ok
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');

# nth_value
query III
SELECT depname, empno,
	nth_value(empno, 2) OVER (
		PARTITION BY depname ORDER BY empno ASC
		ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
		) fv
FROM empsalary
ORDER BY 1, 2
----
develop	7	8
develop	8	9
develop	9	10
develop	10	11
develop	11	NULL
personnel	2	5
personnel	5	NULL
sales	1	3
sales	3	4
sales	4	NULL

# Where either of the the parameters is a constant NULL
query III
SELECT depname, empno,
	nth_value(empno, NULL) OVER (
		PARTITION BY depname ORDER BY empno ASC
		ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
		) fv
FROM empsalary
ORDER BY 1, 2
----
develop	7	NULL
develop	8	NULL
develop	9	NULL
develop	10	NULL
develop	11	NULL
personnel	2	NULL
personnel	5	NULL
sales	1	NULL
sales	3	NULL
sales	4	NULL

query III
SELECT depname, empno,
	nth_value(NULL, 2) OVER (
		PARTITION BY depname ORDER BY empno ASC
		ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
		) fv
FROM empsalary
ORDER BY 1, 2
----
develop	7	NULL
develop	8	NULL
develop	9	NULL
develop	10	NULL
develop	11	NULL
personnel	2	NULL
personnel	5	NULL
sales	1	NULL
sales	3	NULL
sales	4	NULL

# Where either of the parameters is a column that contains NULL values
query III
SELECT depname, empno,
	nth_value(empno, case empno % 3 when 1 then 2 else NULL end) OVER (
		PARTITION BY depname ORDER BY empno ASC
		ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
		) fv
FROM empsalary
ORDER BY 1, 2
----
develop	7	8
develop	8	NULL
develop	9	NULL
develop	10	11
develop	11	NULL
personnel	2	NULL
personnel	5	NULL
sales	1	3
sales	3	NULL
sales	4	NULL

statement ok
CREATE VIEW empno_nulls AS
SELECT depname, case empno % 2 when 1 then empno else NULL end as empno, salary, enroll_date
FROM empsalary

query III
SELECT depname, empno,
	nth_value(empno, 2) OVER (
		PARTITION BY depname ORDER BY empno ASC
		ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
		) fv
FROM empno_nulls
ORDER BY 1, 2, 3
----
develop	NULL	NULL
develop	NULL	7
develop	7	9
develop	9	11
develop	11	NULL
personnel	NULL	5
personnel	5	NULL
sales	NULL	1
sales	1	3
sales	3	NULL

# Where the second parameter (offset) is not a constant
query IIII
SELECT depname, empno, 1 + empno %3 as offset,
	nth_value(empno, 1 + empno %3) OVER (
		PARTITION BY depname ORDER BY empno ASC
		ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
		) fv
FROM empsalary
ORDER BY 1, 2
----
develop	7	2	8
develop	8	3	10
develop	9	1	9
develop	10	2	11
develop	11	3	NULL
personnel	2	3	NULL
personnel	5	3	NULL
sales	1	2	3
sales	3	1	3
sales	4	2	NULL

# Where the second parameter (offset) can be zero (coverage)
query IIII
SELECT depname, empno, empno %3 as offset,
	nth_value(empno, empno %3) OVER (
		PARTITION BY depname ORDER BY empno ASC
		ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
		) fv
FROM empsalary
ORDER BY 1, 2
----
develop	7	1	7
develop	8	2	9
develop	9	0	NULL
develop	10	1	10
develop	11	2	NULL
personnel	2	2	5
personnel	5	2	NULL
sales	1	1	1
sales	3	0	NULL
sales	4	1	4

# Where the first parameter is a constant
query III
SELECT depname, empno,
	nth_value(-1, 2) OVER (
		PARTITION BY depname ORDER BY empno ASC
		ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
		) fv
FROM empsalary
ORDER BY 1, 2
----
develop	7	-1
develop	8	-1
develop	9	-1
develop	10	-1
develop	11	NULL
personnel	2	-1
personnel	5	NULL
sales	1	-1
sales	3	-1
sales	4	NULL

statement error
SELECT depname, empno,
	nth_value(empno) OVER (
		PARTITION BY depname ORDER BY empno ASC
		ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
		) fv
FROM empsalary
----

statement error
SELECT depname, empno,
	nth_value(empno, 2, 3) OVER (
		PARTITION BY depname ORDER BY empno ASC
		ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
		) fv
FROM empsalary
----