yogesphu, I haven't looked up the CHARINDEX function but from what I see in this post, it returns the position number of the character string you are looking for. Since VITAL is at position 16, the function will return 16 if you enter 5, or any number between 1 and 16.

But I think the answer to your question is that if you leave the 5 off completely, it probably defaults to a 1 and starts the search from the beginning of the string.