select distinct SUBSTRING(c.columnname,0,charindex('_',c.columnname)) from table c
declare @aa varchar(100)
set @aa='2011年浙江寿险常规稽核_1saf'
select CHARINDEX('_',@aa)
select substring(@aa,0,CHARINDEX('_',@aa))
select substr(column_name,0,instr(column_name,’_’,1,1)-1) from table_name
如果是oracle的话还是用instr吧