How to count duplicate characters using sql server

Hi,

In this case Scalar value function help you.
Try..


CREATE FUNCTION [dbo].[fnValue](@String varchar(max), @CharToFind char(1))      
RETURNS  INT      
AS      
BEGIN      
 DECLARE @idx int
 DECLARE @countChar int   
 SET @countChar = 0 
 DECLARE @slice varchar(max)      
 
 SELECT @idx = 1      
  IF LEN(@String)<1 OR @String IS NULL 
   RETURN @countChar      
    
 WHILE @idx!= 0      
 BEGIN  
  SET @slice = LEFT(@String, 1)      
  IF(@slice=@CharToFind)
   set @countChar = @countChar + 1
  SET @String = right(@String,len(@String) - @idx)         
  IF LEN(@String) = 0
   BREAK      
 END  
 RETURN @countChar     
END

select dbo.fnValue('chennai','n')
--Output
--2

hope this help you.