SQL Server | STUFF() Function

There are situations when user want to change some portion of the data inserted. The reason may be because of human error or the change in data. For this purpose, stuff() function comes to action. 

STUFF() : 
In SQL Server, stuff() function is used to delete a sequence of given length of characters from the source string and inserting the given sequence of characters from the specified starting index. 

Syntax: 

STUFF (source_string, start, length, add_string)

Where:- 
1. source_string: Original string to be modified. 
2. start: The starting index from where the given length of characters will be deleted and new sequence of characters will be inserted. 
3. length: The numbers of characters to be deleted from the starting index in the original string. 
4. add_string: The new set of characters (string) to be inserted in place of deleted characters from the starting index. 

Note: It is not necessary to have the length of the new string and number of characters to be deleted the same. 

Example 1: 

Output:  

Example 2:  

Output:  

Example 3:  

Output: