Question

怎样获取数据库中某个表中某列中指定字符的数量

如数据表a,字段sname,假如sname中有个值为rerewerewrew，怎样获取r在该字符串中的数量

Answer 1

select len(sname)-len(replace(sname,'r','')) from a

Answer 2

select count(*) from a where sanme = 'rerewerewrew'

Answer 3

select length(sname)-length(replace(sname,'r','')) from a

Answer 4

declare @tmp varchar(2000)
declare @m int
declare @i int
declare @s varchar(1)

set @tmp='rerewerewrew'
set @s='r'
set @i=0
set @m=0
while charindex(@s ,@tmp)>0
begin
set @m=charindex(@s,@tmp)
set @tmp=substring(@tmp,@m+1,len(@tmp))
set @i=@i+1
end
select @i