T-SQL function to check Kaprekar number

T-SQL function to check Kaprekar number.sql

create or alter FUNCTION [dbo].[kaprekar](@n int)
 RETURNS bit
 AS
 BEGIN
 DECLARE @result bit;
 Begin
 If exists ( 
 select 1
 from 
 (select @n number,   square_value,   
 Cast(left(square_value,sq_len-n ) as int) number_left
 ,Cast(stuff(square_value,1,(sq_len-n ),'') as int) number_right 
 from (
 Select @n number,  len(square(@n)) sq_len  
 ,square(@n) square_value   )t
 Cross apply (Select Number FROM master.dbo.spt_values
 where type='P' and Number >=1 and Number <=1000 and Number< len(square(@n)) ) d(n)
 ) t
 where number_left+number_right=number
    
 )
 Select @result=1
 else 
 Select @result=0
 End
    
 RETURN @result; 
    
 END;
    
 /*
 select  [dbo].[kaprekar](9)
 --9 45 55 99 297 703 999
    
 */