[英]T SQL: Inner join in sub select query?
我是WPF开发人员,而不是sql dba ...试图在子选择中进行联接。 我有两个表:tbArticles和tbRegions。 TbArticles包含一个对tbRegions通用的regionCode列。 我正在尝试按地区和国家/地区统计所有文章:
这是我要寻找的结果:
我设法通过内部联接按地区划分了国家:
select distinct r.longName, a.Country
from ises.tbarticles a
INNER JOIN ref.tbRegions r
On a.RegionCode = r.regionCode
order by longName
但是,如何将联接作为子选择获得所需的结果? 我已经尝试过这种方法,但是显然这是不对的。
select (select distinct r.longName from ises.tbarticles a
INNER JOIN ref.tbRegions r
on r.regionCode = a.RegionCode) as 'Region', country, COUNT(*) as 'Total Articles' from ises.tbarticles a, ref.tbRegions r
group by country
order by Region
尝试这个:
select r.longName, a.Country, count(*)
from ises.tbarticles a
INNER JOIN ref.tbRegions r
On a.RegionCode = r.regionCode
group by r.longName, a.Country
order by longName
使用需要先使用GROUP BY子句 ,然后再进行计数
Select r.longName, a.Country, Count(a.*) as ArticleCount
From ises.tbarticles a
INNER JOIN ref.tbRegions r On a.RegionCode = r.regionCode
Group By r.longName, a.Country
尝试这个:
DECLARE @TbArticles TABLE(regionCode INT, Coutry NVARCHAR(MAX), Body NVARCHAR(MAX))
DECLARE @TbRegions TABLE(regionCode INT, Name NVARCHAR(MAX))
INSERT INTO @TbArticles VALUES
(10, N'Australia', 'blah'),
(10, N'Fiji', 'blah'),
(12, N'USA', 'blah'),
(15, N'Belgium', 'blah')
INSERT INTO @TbRegions VALUES
(10, N'Australia'),
(12, N'North America'),
(15, N'Western Europe')
SELECT r.Name, a.Coutry, COUNT(*) AS ArticleCount FROM @TbArticles a
JOIN @TbRegions r ON r.regionCode = a.regionCode
GROUP BY r.regionCode, r.Name, a.Coutry
输出:
Name Coutry ArticleCount
Australia Australia 1
Australia Fiji 1
North America USA 1
Western Europe Belgium 1
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