Union all-distinct and remove duplicates from nested table?

Question

Hi all,
I need a select that will bulk collect some data in my nested table.
I have two tables from which I need to select all the accounts only once.(remove duplicates).
Tried to search on the forum...but no luck.
I have a table with one column:
create table a1(account_no number);
and a second table with 3 columns.
create table a2 (account_no number, name number, desc varchar2 (100));
I have a nested table like:
table of a2%rowtype;
Can I select from this two table in one select and put in my nested table just one row per account?
if a I have in a 2a row like :
1 'test' 'test2'
2 aaaa aa
and in a1 a row like:
1
I want to put in my nested table just (1, null,null and 2,aaaa, aa)) or (1,test,test2 and 2,aaaa, aa). it does no matter what row from those two I insert.
Second question:
If I use:
BANNER
Oracle9i Release 9.2.0.5.0 - Production
PL/SQL Release 9.2.0.5.0 - Production
CORE     9.2.0.6.0     Production
TNS for 32-bit Windows: Version 9.2.0.5.0 - Production
NLSRTL Version 9.2.0.5.0 - Production
SQL>
what is the best solution to remove duplicates from a neste table like mine?
I thought that I can build another nested table and loop in my first nt and for each row I check in there was the same account in previous lines.
it will be like:
for i in 1....nt_first.count loop
for j in 1..i loop
    --check if my line was in previous lines. if it was...do not move it in my second collection
end loop;it is this best option in oracle 9i?

Answer 1

I have a table with one column:
create table a1(account_no number);
and a second table with 3 columns.
create table a2 (account_no number, name number, desc varchar2 (100));
all I need are the accounts. the rest ar extra data
that I can ignore in this step. But if it is
available, it is ok to use it.
using one select in this case is is much better that
trying to remove duplicates parsing some nested table
with FOR many times?
Thankshi,
try to use union. Union automatically removes duplicates between two or more tables.
with t1 AS
       (select '3300000' account_no FROM DUAL UNION
        select '6500000' account_no FROM DUAL union
        select '6500000' account_no FROM DUAL union
        select '6500000' account_no FROM DUAL union
        select '6500000' account_no FROM DUAL
       select * from t1ACCOUNT_NO
3300000
6500000