SQL Stuff is most commonly use inbuilt function in SQL Server. Stuff basically use for manipulate the string. According to MSDN stuff function insert a string into another string. SQL Stuff function takes 4 argument & the syntax of this function is given below:
STUFF (Expression, Start, Length, ReplaceExpression)
In above argument has its own nature
Expression: Its the source string and it has to be modify.
Start: Its the position from where given string have to delete & replace. Expression have to insert. Its a integer value. If you pass negative value on it then stuff returns null.
Length: Its a integer value that tell us how many number of character to delete from the Expression.
Replace Expression: This Replace the expression from the start to length character.