if you're looking for the solution to your actual data, please try to attach files containing some rows from each table you have (payroll, postproduction, salaires charges...)
Otherwise, it is a very common problem when it comes to modeling data.
From what you described above, the solution I have in mind is to CONCATENATE your tables, create aliases on each load (flags), rename every month field from every table to Month (should be the same field name, no matter what..) and link that Month field to your master calendar.
hope it is clear enough.
don't hesitate to read the book mentioned by Rob above for the best approaches, best practices etc
Thanks for your help, i solve my first issue with concatenate tables. So now, i have a new issue if i want to apply a filter by the fild Client-Société, it don't find the infos of the fields Salaires Chargés Primé.
In my tables, i mapped only Date and Nom-Prénom because on the different tables they are the only same fields.