Thread: TWO SAME TABLES, ONE UPDATED. HOW TO SYNC THE OTHER?

Hello

I have two tables -- A and B. The structure of both is the same. Only,
B has many indexes and is used for heavy duty SELECTs. On the other
hand, A only accepts heavy duty INSERTs, so has only one primary key
index.

So my DB design is such that A is only an INSERT table. Periodically,
say every 20 minutes or so, I would like to take all the new INSERTs
from table A and put them into B.

Is there any clever command to accomplish this? I'd rather not write a
PHP script with SQL to take every single new record, and update every
column of a new row in table B. For instance, can I do a replication
of only tables, not databases?

Thanks for any pointers!!

LB

--
Conan O' Brien gets it right!
http://blogs.pcworld.com/tipsandtweaks/archives/004369.html

On May 11, 11:06 pm, "L. Berger" <straightfwd...@gmail.com> wrote:
> Hello
>
> I havetwotables-- A and B. The structure of both is thesame. Only,
> B has many indexes and is used for heavy duty SELECTs. On theother
> hand, A only accepts heavy duty INSERTs, so has onlyoneprimary key
> index.
>
> So my DB design is such that A is only an INSERT table. Periodically,
> say every 20 minutes or so, I would like to take all the new INSERTs
> from table A and put them into B.
>
> Is there any clever command to accomplish this? I'd rather not write a
> PHP script with SQL to take every single new record, and update every
> column of a new row in table B. For instance, can I do a replication
> of onlytables, not databases?
>
> Thanks for any pointers!!
>
> LB

Assuming ID is PK:

INSERT INTO b
    SELECT *
    FROM a
    WHERE NOT EXISTS (
        SELECT 1
        FROM b
        WHERE b.ID = a.ID
    )

This query will run quite slow if tables are large, so - you may in addition create a trigger-updated TIMESTAMP columns and search for changed data through the recent created/updated elements only.