How can I add a character into a specified position into string in SQL SERVER?

Question

I have a varchar field like:

195500
122222200

I need to change these values to:

1955.00
1222222.00

Answer 1

Please try:

select 
   Col,
   REVERSE(STUFF(REVERSE(Col), 1, 2, LEFT(REVERSE(Col), 2)+'.'))
from YourTable

SQL Fiddle Demo