/*
	統(tǒng)計(jì)一個(gè)表中某個(gè)字符出現(xiàn)最多的字母
*/
--創(chuàng)建數(shù)據(jù)測(cè)試環(huán)境
create table #tb(a varchar(200))
insert into #tb
	select 'abcdasdlfjaslk;dfqwoieurwhft'
	union all select 'a;sldkjfal;sopqwhtdlkdafrfgsgasdfh'
	union all select 'asldfkworufgsea87y9oqwpe tchgwccmnqnw3 '

--為字符分拆準(zhǔn)備臨時(shí)表,top 200 是根據(jù)要分拆的字符串的最大長(zhǎng)度而定的,
--在測(cè)試中,因?yàn)閍字段的最大為200,故這里用 top 200
select top 200 id=identity(int,1,1)
	into #aa from
	(select top 100 id from syscolumns) a
	,(select top 100 id from syscolumns) b
	,(select top 100 id from syscolumns) c

--得到結(jié)果
select top 1 substring(a,b.id,1)
	from #tb a,#aa b 
	where substring(a.a,b.id,1)<>''
	group by substring(a.a,b.id,1)
	order by sum(1) desc

drop table #tb,#aa