Re: Query 2 MySQL databases in 1 statement


"Snef" <s.franke@xxxxxxxxxx> wrote in message
news:a6ed7$44c7d63e$3ec24175$26825@xxxxxxxxxxxxxxxxx


mootmail-googlegroups@xxxxxxxxx wrote:
noor.rahman@xxxxxxxxx wrote:
I was wondering how it may be possible to query 2 MySQL databases using
one query statement from PHP.

For instance: SELECT database1.tableA.field1 UNION
database2.tableB.field2.

My concern is, when connecting to MySQL (or sending a query), I only
specify 1 database connection resource ID. How does that play out when
connecting to 2 databases?

Thanks.


As I understand it, the database you specify when connecting to mysql
is your default database. For example, if you connect using "db1",
then to query that database, you can just use "SELECT * FROM table1"
which, because of your default database, is equivalent to "SELECT *
FROM db1.table1". You are still able to access other databases by
fully-qualifying the names, so even if "db1" is your default database,
you can still do something like "SELECT * FROM db2.table2".

I assume that they need to be in the same MySQL?

You mean under the same MySQL instance (server). You connect to an instance,
then create databases using that instance, and you can talk to all of those
databases within that instance. The fact that you can designate one of the
databases as the default database does not mean that you can only talk to
that database.

--
Tony Marston
http://www.tonymarston.net
http://www.radicore.org


.

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