SQL query min startdate max enddate across multiple rows - sql

Question

SQL Server 2008 R2
I have data like this:
+---------+--------+-------------+-------------+
| SchedId | AdId | StartDate | EndDate |
+---------+--------+-------------+-------------+
| 335779 | 179911 | 2017-01-04 | 2017-01-04 |
| 335780 | 179911 | 2017-01-05 | 2017-01-05 |
| ... | | | |
| 335802 | 179911 | 2017-01-31 | 2017-01-31 |
+---------+--------+-------------+-------------+
Across all the records that have an AdId of 179911, I need the minimum StartDate (2017-01-04)and the maximum EndDate (2017-01-31) for a specific date of the month.
I would like to place the data I need for a specific date into a temp table. I tried this:
declare #dt datetime
set #dt = '2017-01-19'
SELECT
MIN(dbo.aoadrundates.StartDate) AS MinStartDate,
MAX(dbo.aoadrundates.EndDate) AS MaxEndDate,
dbo.aoadrundates.AdId AS T_AdId
FROM
dbo.aoadrundates
WHERE
StartDate >= #dt AND EndDate <= #dt
GROUP BY
dbo.AoAdRunDates.AdId,
dbo.aoadrundates.StartDate,
dbo.aoadrundates.EndDate
but I only get the single record with the date I'm selecting, e.g.,
MinStartDate MaxEndDate T_AdId
2017-01-19 2017-01-19 179911
I tried a few examples I found that use cast, min, max as well as a subquery with an inner join, but these have not worked (I think) because I need both min from 1 row and max from another.
Please, if you don't really want to help me, that's fine. If you can help, I would be most grateful. Thank you

Answer 1

So the problem is that you're grouping by the fields you want to aggregate by - dbo.aoadrundates.StartDate and dbo.aoadrundates.EndDate. Assuming you're wanting to group by AdId you can use:
declare #dt datetime
set #dt = '2017-01-19'
SELECT min(dbo.aoadrundates.StartDate) as MinStartDate,
max(dbo.aoadrundates.EndDate) as MaxEndDate,
dbo.aoadrundates.AdId
from
dbo.aoadrundates
where StartDate >= #dt and EndDate <= #dt
group by
dbo.AoAdRunDates.AdId
From the comment "Across all the records" though you might want it repeated for every record with that AdId, in which case you're going to have to use a CTE or similar (in 2012+ there are better ways...):
declare #dt datetime
set #dt = '2017-01-19'
;with cte_MinAndMax as (
SELECT min(dbo.aoadrundates.StartDate) as MinStartDate,
max(dbo.aoadrundates.EndDate) as MaxEndDate,
dbo.aoadrundates.AdId
from
dbo.aoadrundates
where StartDate >= #dt and EndDate <= #dt
group by
dbo.AoAdRunDates.AdId
)
select
dbo.aoadrundates.AdId as T_AdId,
cte_MinAndMax.MinStartDate,
cte_MinAndMax.MaxEndDate,
dbo.aoadrundates.whatever_else_you_want_to_select
from dbo.aoadrundates
left join cte_MinAndMax on dbo.aoadrundates.AdId = cte_MinAndMax.AdId