Re: Java Postgresql temporary table
On Aug 27, 8:21 pm, Arne Vajh=F8j <a...@vajhoej.dk> wrote:
Mark Space wrote:
Owen Jacobson wrote:
Postgres' temporary tables are associated with either the current
transaction or with the connection, depending on how they're created.
They may even have (equally-temporary) indexes created against them.
Thanks for this information. I can't quite envision a use for this, =
but
it's good to know the capability exists.
It is a feature present in many (maybe most) databases.
Sometimes you just can't do it in one SQL statement and
have to stuff data into temporary storage and then
query that.
Arne
DB2 has an interesting feature for this, actually. You can create
named subqueries:
WITH query_one AS (
SELECT * FROM table_a WHERE foo = ?
),
query_two AS (
SELECT * FROM table_b, query_one WHERE ...
)
SELECT * FROM
....
The query optimizer tries to fold them into joins but will resort to
temporary tables for that specific query.
-o