日期:2014-05-18  浏览次数:20427 次

基础问题:统计每一类id的个数?
SQL code

/*统计每一类id的个数(同一类中,相同的id计数是为1。
比如bank-123,bank-123在bank-%类中有两次,最终统计时其个数为1,不是2)
*/

create table #tb(id varchar(50))
insert into #tb values
('bank-123'),
('bank-123'),
('bank-45'),
('bank-ABC'),
('Auto-123'),
('Auto-456'),
('Auto-789'),
('Media-abc'),
('Media-abc'),
('ab12345'),
('ab12348');

/*结果:
bank-%  3
Auto-%  3
Media-% 1
ab%     2
*/




------解决方案--------------------
create table #tb(id varchar(50))
insert into #tb values
('bank-123'),
('bank-123'),
('bank-45'),
('bank-ABC'),
('Auto-123'),
('Auto-456'),
('Auto-789'),
('Media-abc'),
('Media-abc'),
('ab12345'),
('ab12348');

with t
as(
select left(id,case when patindex('%[0-9]%',id)<>0 
then patindex('%[0-9]%',id)-1 else CHARINDEX('-',id)-1 end)+'%' as id
from #tb
)
select id,COUNT(1) as times from t group by id

/*
id times
ab% 2
Auto-% 3
bank% 1
bank-% 3
Media% 2
*/

------解决方案--------------------
SQL code
select 
  left(id,case when charindex('-',id)>0 then charindex('-',id) else patindex('%[^a-z]%',id)-1 end)+'%',
  count(distinct id)
from #tb
group by left(id,case when charindex('-',id)>0 then charindex('-',id) else patindex('%[^a-z]%',id)-1 end)