我希望我能详细解释我的问题,以便你们能理解我。 我创建了一个小示例。
我有一个看起来像这样的表:
City | Name
Berlin | Mike
Berlin City| Peter
Stuttgart | Boris
这是我的查询:
SELECT CASE
WHEN City like '%Berlin%' THEN 'Count Person in Berlin:'
WHEN City like '%Stuttgart%' THEN 'Count Person in Stuttgart:'
WHEN City like '%Dresden%' THEN 'Count Person in Dresden:'
ELSE 'unknown'
END AS Text,
COUNT(Name) AS countPersons
FROM tblTest
GROUP BY City
这是结果:
Count Person in Berlin: 2
Count Person in Stuttgart: 1
但我想要的结果是:
Count Person in Berlin: 2
Count Person in Stuttgart: 1
Count Person in Dresden: 0
我怎样才能得到我想要的结果?希望你能帮助我。
提前致谢。
SQL Fiddle Demo
最佳答案
如果您没有包含城市列表的表,则可以使用子查询。解决这类问题的关键是left outer join
:
select cities.city, count(t.city) as numpeople
from (select 'Berlin' as city union all
select 'Stuttgart' union all
select 'Dresden'
) cities left outer join
tbltest t
on t.city = cities.city
group by cities.city;
如果你也想拥有'unknown'
,那么可以使用full outer join
:
select coalesce(cities.city, 'unknown') as city, count(t.city) as numpeople
from (select 'Berlin' as city union all
select 'Stuttgart' union all
select 'Dresden'
) cities full outer join
tbltest t
on t.city = cities.city
group by coalesce(cities.city, 'unknown');
关于sql - MSSQL : Display Rows for a Select with Case and Count even if Count = 0,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/23245869/
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