if variable filled in then print something

[isabellek]

I am trying to display some code only if a variable is filled in. How would I do this?
I have a mysql column called "img_2" which I'd like to show some code only if there is a value in img_2. So something like:

if "img_2" is filled in then

print
<img src=¥"img/{$row['img_2']}¥">

Thanks

[bike5]

if(!empty($var)) print
if(strlen($var)!=0) print
just a couple ways