Update query problem (SQLite for iPhone SDK)

I have a table column containing name of images (e.g Apple.jpg). All image names have .jpg as extension.

How do开发者_Go百科 I update the extension from .jpg to .png using update statement of SQLite?

Thanks!

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UPDATE mytable
   SET name = substr(name, 1, length(name) - 4) || '.png'
 WHERE name LIKE '%.jpg'

Of course, this won't convert the images themselves from JPEG to PNG. (Just to be sure. :-)