Return empty string instead of NULL in query

Hi Experts

I am running a query to get return the file name of a picture.    It should either return the filename.jpg or be an empty string but when the record has no picture because the picture has been deleted it returns a NULL value rather than an empty string.  Even though I am replacing using NULL as criteria and return '' I still get NULL in result set.   Is there a way around this?

Thanks
Jon

case T0.[PicturName]
when NULL THEN ''
else T0.[PicturName]
END 'Picture',

Select allOpen in new window