Question

How can I achieve an insert query on 2 tables that will insert the primary key set from one table as a foreign key into the second table.

Here’s a quick example of what I’m trying to do, but I’d like this to be one query, perhaps a join.

INSERT INTO Table1 (col1, col2) VALUES ( val1, val2 )
INSERT INTO Table2 (foreign_key_column) VALUES (parimary_key_from_table1_insert)

I’d like this to be one join query.
I’ve made some attempts but I can’t get this to work correctly.

Answer 1

Despite what others have answered, this absolutely is possible, although it takes 2 queries made consecutively with the same connection (to maintain the session state).

Here’s the mysql solution (with executable test code below):

INSERT INTO Table1 (col1, col2) VALUES ( val1, val2 );
INSERT INTO Table2 (foreign_key_column) VALUES (LAST_INSERT_ID());

Note: These should be executed using a single connection.

Here’s the test code:

create table tab1 (id int auto_increment primary key, note text);
create table tab2 (id int auto_increment primary key, tab2_id int references tab1, note text);
insert into tab1 values (null, 'row 1');
insert into tab2 values (null, LAST_INSERT_ID(), 'row 1');
select * from tab1;
select * from tab2;
mysql> select * from tab1;
+----+-------+
| id | note  |
+----+-------+
|  1 | row 1 |
+----+-------+
1 row in set (0.00 sec)

mysql> select * from tab2;
+----+---------+-------+
| id | tab2_id | note  |
+----+---------+-------+
|  1 |       1 | row 1 |
+----+---------+-------+
1 row in set (0.00 sec)