The fields I've underlined have the same data. If I rename the field I create a loop. How can I avoid this loop? I've red about concatenation of table or Join but I'm not sure I can do it.
1.- if 'scarico' table has all possible values for 'cliente', and 'codice' from 'mailing' table is a subset of data, you can comment or rename that field.
2.- Check if is valid the relation between 'carico' and 'mailing' trhough 'codfornitore', if not, just rename or comment 'codfornitore', nd rename 'codice' to 'cliente'
3.- if 'scarico' and 'carico' are related as 'header' and 'details' you can join them.
As you can see, it is all about the relation of every single table with the rest.
Greetings!! Fabián Quezada (QFabian) did it work for you? give like and mark the solution as accepted.