SQL Optimization Help

Question

Hi,
I'm relatively new to SQL and I'm trying to figure out a good way to run a select statement multiple times (with different parameters) and only have one results table.
SELECT *
FROM table
WHERE date=&1
This is what I'm doing now, but I'm sure it's not optimal:
SELECT *
FROM table
WHERE date=date1
UNION ALL
SELECT *
FROM table
WHERE date=date2
UNION ALL
SELECT *
FROM table
WHERE date=date1
ect....
Help please.

Answer 1

Hi,
Can you insert the parameters into a global temporary table? If so, you could join to the global temporary table like this:
/* Set up demo table */
create table source_table (
id number,
date_field date
create index idx_date_field on source_table (date_field);
/* Insert 10000 dates */
insert into source_table
select rownum, trunc(sysdate) + rownum from dual connect by rownum < 10000;
commit;
/* Set up the global temporary table */
create global temporary table gtt_dates (date_val date) on commit preserve rows;
/* Insert 10 random dates */
insert into gtt_dates
select * from (select date_field from source_table order by dbms_random.random) where rownum <= 10;
/* Demo query */
select a.*
from source_table a,
gtt_dates g
where a.date_field = g.date_val;
Regards,
Melvin