SQL Server - Display two different dates on two different lines - sql

Question

I'm currently struggling to get my query to display two dates on two lines. i.e. I have two lines, with two columns for two dates. I need one line to have null then date, the second line to have date then null. Example shown in image below - only one of these dates needs to show up per line.
Two lines two dates
Google has not been my friend thus far because it's a rather obscure thing to try and describe to the search engine. Any help would be greatly appreciated. Full query is below:
WITH CTE AS
(
SELECT *,
ROW_NUMBER() OVER(PARTITION BY person_code ORDER BY unit_instance_code) AS rn
FROM learner_aims
)
SELECT DISTINCT p.person_code [ID],
p.forename [Forename],
p.surname [Surname],
uio.long_description [CourseDesc],
CASE rn
WHEN 1 THEN NULL
WHEN 2 THEN CONVERT(DATE, sub.[GIL Start Date], 103)
END AS [GIL Start Date],
CASE rn
WHEN 1 THEN CONVERT(DATE, sub.[Non-GIL Start Date], 103)
WHEN 2 THEN NULL
END AS [Non-GIL Start Date]
-- CONVERT(DATE, sub.[GIL Start Date], 103) [GIL Start Date],
-- CONVERT(DATE, sub.[Non-GIL Start Date], 103) [Non-GIL Start Date]
FROM people p
INNER JOIN learner_aims la ON p.person_code = la.person_code
INNER JOIN unit_instance_occurrences uio ON uio.uio_id = la.uio_id
INNER JOIN cte ON cte.person_code = p.person_code
LEFT JOIN (SELECT DISTINCT p.person_code [ID],
p.forename [Forename],
p.surname [Surname],
MIN(fy22.earlieststartdate) [GIL Start Date],
MIN(fy22sub.earlieststartdate) [Non-GIL Start Date]
FROM people p
INNER JOIN learner_aims la ON p.person_code = la.person_code
INNER JOIN unit_instance_occurrences uio ON uio.uio_id = la.uio_id
LEFT OUTER JOIN (
SELECT p.person_code [ID],
p.forename [Forename],
p.surname [Surname],
uio.course_occurrence_code [CourseCode],
uio.long_description [CourseDesc],
uio.owning_organisation [OwningOrg],
uio.offering_organisation [OfferingOrg],
la.uio_id [uio_id],
MIN(CONVERT(DATE, la.start_date, 103)) [EarliestStartDate]
FROM people p
INNER JOIN learner_aims la ON p.person_code = la.person_code
INNER JOIN unit_instance_occurrences uio ON uio.uio_id = la.uio_id
WHERE la.ilr = 'Y'
AND la.funding_year = '22'
AND (
uio.course_occurrence_code LIKE 'GIL%'
OR uio.course_occurrence_code LIKE 'SEED%'
)
GROUP BY p.person_code,
p.forename,
p.surname,
uio.course_occurrence_code,
uio.long_description,
uio.owning_organisation,
uio.offering_organisation,
la.uio_id
) [FY22] ON fy22.id = la.person_code
LEFT OUTER JOIN (
SELECT p.person_code [ID],
p.forename [Forename],
p.surname [Surname],
uio.course_occurrence_code [CourseCode],
uio.long_description [CourseDesc],
uio.owning_organisation [OwningOrg],
uio.offering_organisation [OfferingOrg],
la.uio_id [uio_id],
MIN(CONVERT(DATE, la.start_date, 103)) [EarliestStartDate]
FROM people p
INNER JOIN learner_aims la ON p.person_code = la.person_code
INNER JOIN unit_instance_occurrences uio ON uio.uio_id = la.uio_id
WHERE la.ilr = 'Y'
AND la.funding_year = '22'
AND uio.course_occurrence_code NOT LIKE 'GIL%'
AND uio.course_occurrence_code NOT LIKE 'SEED%'
AND la.person_code IN (
SELECT la.person_code [ID]
FROM people p
INNER JOIN learner_aims la ON p.person_code = la.person_code
INNER JOIN unit_instance_occurrences uio ON uio.uio_id = la.uio_id
WHERE la.ilr = 'Y'
AND la.funding_year = '22'
AND (
uio.course_occurrence_code LIKE 'GIL%'
OR uio.course_occurrence_code LIKE 'SEED%'
)
)
GROUP BY p.person_code,
p.forename,
p.surname,
uio.course_occurrence_code,
uio.long_description,
uio.owning_organisation,
uio.offering_organisation,
la.uio_id
) [FY22SUB] ON fy22sub.id = la.person_code
WHERE la.funding_year = '22' AND la.ilr = 'Y'
GROUP BY p.person_code,
p.forename,
p.surname
HAVING MIN(CONVERT(DATE, fy22sub.earlieststartdate, 103)) > MIN(CONVERT(DATE, fy22.earlieststartdate, 103))
) sub ON sub.id = la.person_code
WHERE la.funding_year = '22' AND la.ilr = 'Y'
ORDER BY 3, 2

Answer 1

That's not clear what determines if the row is first or second, I did it in base of the text in the second column as it's the only thing that changes.
So the idea here is to enumerate the rows (order by 2) and then to show the date as you want:
declare #t table (id int, CourseDesc varchar(100), [GIL Start Date] date, [Non-GIL Start Date] date);
insert into #t values(21571, 'text1', '20151116', '20160222'), (21571, 'text2', '20151116', '20160222');
with cte as
(
select *,
row_number() over(partition by id order by CourseDesc)as rn
from #t
)
select id, CourseDesc,
case rn
when 1 then null
when 2 then [GIL Start Date]
end as [GIL Start Date],
case rn
when 1 then [Non-GIL Start Date]
when 2 then null
end as [Non-GIL Start Date]
from cte;