How to compare 2 NVARCHAR(MAX) columns in same table ?

Question

I have 2 strings i am trying to compare them ,If user changes some data then insert should happen to change log table .
here is the condition i am using it
If dbo.RemoveMultipleSpacesItr(@ProgBusSolPrev) <> dbo.RemoveMultipleSpacesItr(@ProgBusSol)
begin
Insert into ptt_pmt_import_ch(ProgramID,ColumnName,Prev_Value,New_Value,UpdatedBy) values(@Programid,'Solution to Problem',@ProgBusSolPrev,@ProgBusSol,@UpdatedBy)
end
My Scalar Function to compare 2 strings and replace spaces in strings.
CREATE FUNCTION dbo.RemoveMultipleSpacesItr(@str NVARCHAR(MAX))
RETURNS NVARCHAR(MAX)
AS
BEGIN
WHILE CHARINDEX(' ', @str) > 0
SET @str = REPLACE(@str, ' ', '');
RETURN @str;
END
If my Input values for
@ProgDescriptionPrev='These issues are creating missed appointments and unnecessary scheduling techs on appt that are not needed. This impacts areas that are in an overbooking situation. Potentially overbooks appts during specific time of day, and increases Appt misses. Potentially decreasing Appts met by .3%, which has potential customer services impacts of 10K per year. This impacts Load Supervisors as they have to manually calculate worksteam percentage allocations. Estimating 20 users a day * 30mins= 50hrs week =1.1 Supervisor HC= 90K year. IT HelpDesk Tickets (sometimes duplicate) are also opened by front-line agents and are unable to be resolved. So this is a total of about 100k+ a year in cost savings/avoidance.'
@ProgDescription='These issues are creating missed appointments and unnecessary scheduling techs on appt that are not needed. This impacts areas that are in an overbooking situation. Potentially overbooks appts during specific time of day, and increases Appt misses. Potentially decreasing Appts met by .3%, which has potential customer services impacts of 10K per year. This impacts Load Supervisors as they have to manually calculate worksteam percentage allocations. Estimating 20 users a day * 30mins= 50hrs week =1.1 Supervisor HC= 90K year. IT HelpDesk Tickets (sometimes duplicate) are also opened by front-line agents and are unable to be resolved. So this is a total of about 100k+ a year in cost savings/avoidance.'
Only difference in strings is space(' ')
if there is no difference in strings avoiding spaces in strings, i need to insert into change log. But using above query even there is no change in string values it inserts in to change log table.Please help on this,i need solution for this
sonali malla

Answer 1

Hi,,,
Are you lecturing my dynamic script? Thither is a solution for this problem - we can convert all column values to nvarchar(max) first - most common types can be converted to nvarchar(max) and only some exotic types cannot be converted.
Here is the script using nvarchar(max):
CREATE TABLE Test1(id INT,col2 INT,col3 INT, col4 int, col5 varchar(10), col6 date)
CREATE TABLE Test2(id INT,col2 INT,col3 INT, col4 int, col5 varchar(10), col6 date)
INSERT INTO Test1 VALUES (1,2,3,9,'q', '20120101'),(4,5,6,10,'z','20120404')
INSERT INTO Test2 VALUES (1,2,7,8, 'm','19990101'),(4,8,6,12, 'dd','20110505')
declare @sql nvarchar(max), @Cols nvarchar(max)
select @Cols = stuff((select ',(cast(' + QUOTENAME(column_name) + ' as nvarchar(max)),' +
QUOTENAME(column_name,'''') + ')' from Information_schema.columns C
where C.TABLE_SCHEMA = 'dbo' and c.TABLE_NAME = 'Test1' and c.COLUMN_NAME <> 'id'
order by c.COLUMN_NAME for XML path('')),1,1,'')
set @sql = 'SELECT t1.c as [Column Name] , t1.col as [Expected Value], t2.col as [Actual Value]
FROM (select id, c, col from Test1 cross apply (values' + @Cols + ' ) d(col, c) ) t1
INNER JOIN
(select id, c, col from Test2 cross apply (values' + @Cols+ ' ) d(col, c) ) t2
ON t1.id=t2.id AND t1.c=t2.c
WHERE t1.col<>t2.col
Order by t1.c'
print @sql
execute (@sql)
If Any other Concern, let me know.
Thanks :-)