UPDATE `program` SET `title` = `subtitle` WHERE `title` = 'Cine'
for example writes the subtitle into the title anywhere where "Cine" is in the title. You can change this to any string that gets used as placeholder.
I noticed that some channels that get populated using xmltv tend to have a generic title and the actual title of the show shows only in the subtitle. I needed to fix this, so I wrote a small SQL statement to do it.