Hopefully quick SQL question - globally updating a field value
If I have two fields, fieldA and fieldB, where fieldA is populated, but fieldB is not, I know I can update fieldB globally to equal the value of fieldA, using:
SET fieldA = fieldB
But how can I do the same, but add a prefix to the value of fieldB?
My use case is that fieldA contains a filename, and I would like to globally update fieldB to equal the full path to the file as well as the filename
So if fieldA = 'my_image.jpg' I want to globally update fieldB to equal 'http://www.mywebsite.com/images/my_image.jpg'.