Split the column into two based on conditions

Question

Hello,
I have 2 tables Country and Continent.
Continent has the data like this
ID               Name
1               Asia
2              Africa
3              North America
4             South America
Country has 
ID                Name                 ContinentID            Population
1                  China                  1                                 2000
2                  India                   1                                 1500
3                  Ethiopia              2                                 7500
4                  United States       3                                5000
I need the count of countries for each continent  break into two columns based on the population. One column showing the count of countries with population <= 2000 and the other column should show the count of countries with population >2000
How can I achieve this?
Please help.
Thank you

Answer 1

Here you go:
DECLARE @continent TABLE (ID INT, Name VARCHAR(30))
INSERT INTO @continent (ID, Name) VALUES (1, 'Asia' ),(2, 'Africa' ),(3, 'North America'),(4, 'South America')
DECLARE @country TABLE (ID INT, Name VARCHAR(30), ContinentID INT, Population INT)
INSERT INTO @country (ID, Name, ContinentID, Population) VALUES (1, 'China', 1, 2000),(2, 'India', 1, 1500),(3, 'Ethiopia', 2, 7500),(4, 'United States', 3, 5000)
SELECT COUNT(*), ct.name
FROM @country c
INNER JOIN @continent ct
ON c.ContinentID = ct.ID
GROUP BY ct.name
and for the high/low:
DECLARE @continent TABLE (ID INT, Name VARCHAR(30))
INSERT INTO @continent (ID, Name) VALUES (1, 'Asia' ),(2, 'Africa' ),(3, 'North America'),(4, 'South America')
DECLARE @country TABLE (ID INT, Name VARCHAR(30), ContinentID INT, Population INT)
INSERT INTO @country (ID, Name, ContinentID, Population) VALUES (1, 'China', 1, 2000),(2, 'India', 1, 1500),(3, 'Ethiopia', 2, 7500),(4, 'United States', 3, 5000)
;WITH popRank AS (
SELECT ROW_NUMBER() OVER (PARTITION BY ct.ID ORDER BY POPULATION DESC) AS row, ct.name AS continentName, c.name AS countryName, c.population, c.ContinentID
FROM @country c
INNER JOIN @continent ct
ON c.ContinentID = ct.ID
SELECT r.countryName AS biggestPopCountry, r.population as biggestPopCount, r1.countryName AS lowestPopCountry, r1.population as lowestPopCount
FROM popRank r
INNER JOIN popRank r1
ON r.ContinentID = r1.ContinentID
AND r1.row = (SELECT MAX(row) FROM popRank WHERE ContinentID = r.ContinentID)
AND r.row = 1