Selecting only last part of the data - sql

Question

I've the following data
I want the outcome to be like this:
For Albania, I want to select minimum and maximum values of date for the last value of City_Code (here, it's 20008) of Albania (The min value of date for 20008 is 18.01.2013, and max value for 20008 is 20.01.2013). For Croatia the last value of City_Code is 'zero', so we shouldn't select anything (if last value of 'City_Code' is zero, don't select it at all). For Slovenia, the last value of City_Code is 70005, so we select minimum and maximum values of corresponding dates (here maximum and minimum values are 22.01.2013). How should code look like? I don't have any idea. Thanks in advance

Answer 1

Try this...
;
WITH cte_countries ( Country, City_code, CurrentDate, LatestRank )
AS ( SELECT Country ,
City_code ,
CurrentDate ,
RANK() OVER ( PARTITION BY country ORDER BY CurrentDate DESC ) AS LatestRank
FROM #countries
WHERE City_code != 0
)
SELECT *
FROM cte_countries
WHERE LatestRank = 1

Answer 2

SELECT Country,
max(City_code),
min(DATE),
max(Date)
FROM T as T1
WHERE City_code = (SELECT TOP 1 City_Code
FROM T WHERE T.Country=T1.Country
ORDER BY Date DESC)
GROUP BY Country
HAVING max(City_Code)<>'0'

Answer 3

Try this:
With Cities
AS (
select Country, City_Code, Min([Date]) Date1, Max([Date]) Date2,
ROW_NUMBER() OVER(PARTITION BY Country ORDER BY Country, City_Code DESC) Seq
from MyCountryCityTable t
group by t.Country, t.City_Code
)
Select
Country,
NULLIF(City_Code,0) City_Code,
CASE WHEN City_Code = 0 THEN NULL ELSE Date1 END Date1,
CASE WHEN City_Code = 0 THEN NULL ELSE Date2 END Date2
From Cities Where Seq = 1
Order by Country
EDIT:
Version without the common table expression (WITH):
Select
Country,
NULLIF(City_Code,0) City_Code,
CASE WHEN City_Code = 0 THEN NULL ELSE Date1 END Date1,
CASE WHEN City_Code = 0 THEN NULL ELSE Date2 END Date2
From (select Country, City_Code, Min([Date]) Date1, Max([Date]) Date2,
ROW_NUMBER() OVER(PARTITION BY Country ORDER BY Country, City_Code DESC) Seq
from MyCountryCityTable t
group by t.Country, t.City_Code) Cities
Where Seq = 1
Order by Country