Comments on: SQL SERVER – UDF – Remove Duplicate Chars From String

By: SQL SERVER – Weekly Series – Memory Lane – #006 « SQL Server Journey with SQL Authority

Sat, 08 Dec 2012 01:30:34 +0000

[...] UDF – Remove Duplicate Chars From String This was a very interesting function I wrote in my early career. I am still using this function when I have to remove duplicate chars from strings. I have yet to come across a scenario where it does not work so I keep on using it till today. Please leave a comment if there is any better solution to this problem. [...]

By: SQL SERVER - Remove Duplicate Characters From a String Journey to SQL Authority with Pinal Dave

Mon, 31 Dec 2007 02:34:40 +0000

[...] my previous article of Remove Duplicate Chars From String here is another great article written by Madhivanan where similar solution is suggested with alternate method of Number table approach. Check out [...]

By: Madhivanan

Madhivanan — Sat, 29 Dec 2007 07:19:14 +0000

Here is non while loop approach

http://sqlblogcasts.com/blogs/madhivanan/archive/2007/12/29/remove-duplicate-characters-from-a-string.aspx

By: srikanth

srikanth — Fri, 14 Dec 2007 11:06:32 +0000

Hello sir,
I am new to DB and sql server 2005, this site is very helpful,
thanks a lot.
Sir I am using this function ‘Removing duplicate chars string from one large string’,
I found that while loop (while @count<=255) in this function is unnecessarily checking the condition even after removing duplicates, what I think is, it should come out of the loop when string doesn’t contain any duplicate chars.

Like when I am calling the function:-

SET CONCAT_NULL_YIELDS_NULL OFF
SELECT dbo.Remove_duplicate_instr(3,123456789123456456)

According to the function @count = 3 and it is checking the condition till @count = 258,
But we get the output at @count =12 for the above and it should come out of the loop at
@count = 16.

If I am using if condition

if (@str = ”)
break

After SET @count=@count+@datalen_tocheck
Iam getting the output @count=12 and it is coming out of the loop at @count=16 . I think by this, we can avoid repeated checkings after removing duplicates.

Is it not a performance issue?
Just tell me sir whether I am correct or not.

thanks,
srikanth.

By: C

Mon, 10 Dec 2007 16:44:06 +0000

Hi,

Don’t we need to trim any blank charactors