PS 1.7 Bulk Attribute update for my products

[Jimmy Labuche]

Hello everyone !

I'm having a big problem right now that has been generated by myself in the design of attribute groups.
I explain in detail:

I have a first attribute group "Size" containing the values S, M, L, XL etc ...
I have a second "Poster Size" attribute group containing the values 'S - 10 x 14', 'M - 45 x 32' etc ...

The real problem is that we did not initially think about expanding the types of products we would offer.
 
So I have products (posters) in the category "posters" having the values of the first group of attributes to define the declensions.
I would like on these products:
To modify the declensions where:

S becomes 'S - 10 x 14'
M becomes 'M - 45 x 32'
etc ...

I guess this is possible via a SQL query, but it totally exceeds my skills.

Can anyone help me ?

Thank you in advance !

Regards,

PRESTASHOP: 1.7.2.4