query for a time interval

Hello everybody,

I'm looking for an elegant SQL statement that will work in
Postgresql, MySQL and ORACLE.
The query will be executed by Java client.

To have this query for Postgresql is priority number one.

In this query I try to get a list of message Ids that expired.

time_to_live is in seconds.

SELECT id
FROM mq
WHERE now - start_date > time_to_live;

I have a following table:

CREATE TABLE mq
{
msg_id INTEGER,
retry_date TIMESTAMP NOT NULL DEFAULT ('now'::text)::timestamp(1),
start_date TIMESTAMP NOT NULL DEFAULT ('now'::text)::timestamp(1),
time_to_live INTEGER
}

Thanks!
Mark.

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