Question

How can we copy data from one table into another table which doesn’t exist in the first one. In table one of the column is primary key.

INSERT INTO table SELECT * FROM db2.table; 
ERROR 1062 (23000): Duplicate entry '100001' for key 'id_UNIQUE'

Answer 1

You can use the predicate NOT IN to do so like this:

INSERT INTO table1 
SELECT * 
FROM db2.table2 
WHERE table1ReferenceID NOT IN(SELECT id_UNIQUE FROM table1);

This will checks whether this table1ReferenceID found in the first table or nor. Therefore, the SELECT clause will select all the rows from the second tables except those that is already presented in the first table table1.

Note that: the column table1ReferenceID is the reference of the id_UNIQUE in the second table.

Other alternatives for this, is to LEFT JOIN as suggested by @HamletHakobyan‘s answer and NOT EXISTS.

• See it in action