在表之间移动MySQL行？

Question

I am trying to insert some columns from table_a (ptb_registrations) INTO table_b (ptb_users).

At the moment I have this query which updates the columns in table b from table a, but instead of it overwriting existing information which is currently stored in ptb_users I want it to insert a new row.

My table ptb_users looks like this:

id (auto inc)    |   first_name   |         email   
     1                  john            john@email.com   

...and my table ptb_registrations looks like this:

id (auto inc)    |   firstname   |         email   
     2                  eric            john@email.com   

So now I want to insert the columns firstname and email from ptb_registrations into ptb_users.first_name and ptb_users.email as a new row?

Can someone please point me in the right direction?

This works on update

$query = "UPDATE ptb_users
SET first_name = (
  SELECT firstname
  FROM ptb_registrations
)";

mysql_query($query)or die('Could not update members: ' . mysql_error());

I have tried:

$query = "INSERT INTO ptb_users.first_name = (
  SELECT firstname
  FROM ptb_registrations
)";

mysql_query($query)or die('Could not update members: ' . mysql_error());

Answer 1

Here's a link documenting INSERT in MySQL http://dev.mysql.com/doc/refman/5.5/en/insert.html

  INSERT INTO ptb_users (first_name, email)
  SELECT firstname, email
  FROM ptb_registrations;

Answer 2

You'll want to do your insert statement like this:

INSERT INTO ptb_users (firstname)
  SELECT firstname
  FROM ptb_registrations