request sql update all articles, image and date

Hello,

I need your help to write 2 request mysql.

after having made a migration of my site wp,

images at a not working

I have an image by default and I would like to set all my articles.

the id of the image is 631 postmeta.

my request have to say to add image as the one for all posts

(I would do that by sql, and not use plugins)

And there are ways to make a request to put to-day all the articles of his wordpress site?

For example change the date 20.04.16 in 04.30.16 for all articlles with a request

Thank you