Answer by Dave P 1

I think I misunderstood your question. My previous post assumed you were looking for adjacent characters. This will do what you want: count the instances of @c in @in.

CREATE FUNCTION dbo.fn_strcount
(
  @in varchar(8000),
  @c char
) RETURNS integer AS
BEGIN

    DECLARE @i int,
        @l int,
        @out int ;

    DECLARE @ch char ;

    SELECT  @l = LEN(@in),
            @i = 1,
            @out = 0 ;

    WHILE ( @i <= @l )
        BEGIN

            SET @ch = SUBSTRING(@in, @i, 1) ;

            IF ( @ch = @c )
                SET @out = @out + 1 ;

            SET @i = @i + 1 ;

        END ;

    RETURN (@out) ;

END ;