深入细致的探讨一下这个SQL语句的问题，再次求教

Question

说来说去就是那几个函数
select *
from tablename
where (charindex('-', columnname) = 0 and columnname = '6') or (charindex('-', columnname) > 0 and left(columnname, charindex('-', columnname) - 1) = '6')

Answer 1

楼主这样试一下。select *
from tablename
where left(columnname, charindex('-', columnname) - 1) = '6'union allselect * from tablename where charindex('-', columnname)=0 and left(columnname,1) ='6'

Answer 2

... where 字段 like '6-%'

Answer 3

select *
from tablename
where left(columnname, case charindex('-', columnname) when 0 then 1 else charindex('-', columnname)-1 end ) = '6'

Answer 4

declare @t table (c varchar(1000))
insert @t 
 select '1' union 
 select '6-7-8-9' union 
 select '10-11-12-13' union 
 select '111-2323-8998'
select rtrim(c)
from @t
where right(left(c, charindex('-', c+'-') - 1),1) = '1'/*                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
---------------------
1
111-2323-8998
*/

Answer 5

select *
from tablename
where left(columnname, charindex('-', columnname) - 1) = '6' and charindex('-', columnname) > 0

Answer 6

declare @t table (c varchar(1000))
insert @t 
 select '1' union 
 select '6-7-8-9' union 
 select '10-11-12-13' union 
 select '121-2323-8998'
select rtrim(c)
from @t
where right(left(c, charindex('-', c+'-') - 1),1) = '1'--------------------------这个也不是楼主想要的 因为把 '121-2323-8998' 也选出来了 

Answer 7

应该要写个自定义函数来判断吧。
因为包含的算法用现有的SQL函数实现不了，关键就是 区别第一个'-'前面的
字符串是否所有单个字符都是同一个字符组成的情况
如:'121'和'111'就是不同的