How to insert data from multi tables to one table in Oracle?

Question

I'd a trouble with inserting data from 3 table: A (id, name), B (id, name), C (id, name). They have the same field like that. How can I insert data from 3 tables above into table D (id, name)?

Answer 1

You could use UNION or UNION ALL

INSERT INTO table_d(id, name)
SELECT id, name
FROM table_a
UNION ALL 
SELECT id, name
FROM table_b
UNION ALL 
SELECT id, name
FROM table_c;   

If you want to remove duplicate rows in 3 tables, change UNION ALL to UNION. Refer information about union vs union all