1. Duplicate content->; This is normal. It is normal for the database to have duplicate data. Even in a table, duplication is normal if there is no primary key in the table. In the current work, there is only one thing, that is, deduplication. But you said it was in two different tables. If there is duplication, it is more normal.

2. have the same field-> this is too normal. You see, suppose there are two tables, dept and emp, and both tables will contain deptno. This is also normal, that is, these two fields must be used as primary foreign keys and must be available.