I have come up with the following Script (It does not work)
INSERT INTO Table_1 ( item1, item2, item3, item4, condition_a, item5, item6 )
SELECT Table_2.item1, Table_2.item2, Table_2.item3, Table_2.item4, Table_2.condition_b, Table_2.item5, Table_2.item6
FROM Table_2;
Where table_1.item1 =...