Mysql select multiple records

Question

I have 3 tables abc ab and c all are related through an id a.id = b.id = c.id

My task is to select all rows from ab and c where a.date is older than 6 months and insert them into a new db for archiving.

Here is what I have so far:

insert into dbArchive.a select * from db.a where receivedDate < CURRENT_DATE() - INTERVAL 6 MONTH;`

This seems to select all entries from table a that are older than 6 months and insert them into the archive db table a.

What is the best and most efficient way to find all rows from tables b and c that have the same id and insert them to the archive db tables b and c?

I have over 1 million records that are older than 6 months so I am weary about performance issues.

Answer 1

After inserting into dbArchive.a as you have done here, you can run the following to insert into dbArchive.b and same way for dbArchive.c .

INSERT INTO dbArchive.b(id, etc..) 
  SELECT db.b.id, etc.. 
  FROM dbArchive.a INNER JOIN db.b ON dbArchive.a.id = db.b.id;

Answer 2

So after playing around for a while this seems to be the best approach I have found that actually works:

INSERT INTO archive.b SELECT * FROM db.b WHERE `id` IN( SELECT `id` FROM archive.a )

I am not sure if this is the most efficient method but it gets the job done