You can use the Prepend formula to combine the text of two columns into one as well as to add constant text. Prepend takes the current column and adds the text you choose to the start of it, and puts the result in a new column. (Append adds the text you choose to the end instead.)

In your database, there is a field which contains fragments of website links that refer to a website, www.yoursite.com. The entries contain values like /about/ and /contact/. You want to make these into full links, but you don’t want to edit each link by hand.

Click the link fragment column, go to Add Formula, choose Prepend, and then Constant. In the pop-up, enter the beginning part of the link, e.g. http://www.yoursite.com. A new column appears with the full link, e.g. http://www.yoursite.com/about/ and http://www.yoursite.com/contact/.