when if i send Arabic characters means sql considering as 'question mark' why?

ALTER FUNCTION [dbo].[Contains_Arabic_English_Char] ( @RowStr nvarchar(1000) ) 
RETURNS Char 
AS

BEGIN

declare @index int;
declare @charac char(1);
SELECT @index = 0;
declare @thisChar char(1);
while(@index <= LEN(@RowStr))
begin
 SELECT @thisChar = SUBSTRING(@RowStr,@index,1);

-- print @index
-- print ASCII(@thisChar) 
if (AS开发者_JAVA百科CII(@thisChar) BETWEEN 153 and 158 OR ASCII(@thisChar) BETWEEN 162 and 218 OR                                           ASCII(@thisChar) BETWEEN 223 and 254 )
--if (unicode(@thisChar) BETWEEN U+0600 and U+06FF)

begin SELECT @index=-1; 
BREAK;
 end 
else 
SELECT @index=@index+1; 
end 
-- print @index 
-- print LEN(@rowStr)
if (@index =-1)
BEGIN
SET @charac = 'A' --''found a Arabic char!'
END 
ELSE
BEGIN 
SET @charac = 'E' --'no Arabic Char found!' END

RETURN @charac

END

EXEC select [dbo].[Contains_Arabic_English_Char] ('ش')

it was showing ouput As "E"

so i have checked up like this manner

select ascii('ش')

it was given output as 63

63 is nothng but ascii value for Question mark '?"

---

Try using UNICODE() instead of ASCII(), because you're dealing with unicode characters.

ASCII():

Returns the ASCII code value of the leftmost character of a character expression.

UNICODE():

Returns the integer value, as defined by the Unicode standard, for the first character of the input expression.

Note, to run a test:

-- Returns 63:
select ASCII('ش')
-- Still returns 63:
select UNICODE('ش')
-- Returns 1588. Note the N before the character, to indicate it's a unicode string
select UNICODE(N'ش')

Update: A few things you need to change:

declare @thisChar char(1);

should be:

declare @thisChar nchar(1);

Then when you check that character, just do a straight swap from using ASCII() to UNICODE()