PostgresSQL: backup table as UPDATE statements

Question

I've made a mistake. I've updated a table without where... Fortunatelly I have a backup. I cant delete the table and restore it, because of foreign key restrictions... I want to save the original table as UPDATE statements to restore the values, ¿how can I do that?

Answer 1

1. Import the backed up table with another name (ie. backup).
2. Update the original table with an UPDATE JOIN.

Example:

    UPDATE mytable
    SET mytable.c1 = backup.c1, mytable.c2 = backup.c2,
    FROM backup
    WHERE mytable.id = backup.id;