Comments on: Sorting PL/SQL Collections, the quite simple way (part two: Have the SQL Engine do the heavy lifting)

By: Janos Ujvari

Janos Ujvari — Fri, 30 Sep 2011 09:32:24 +0000

Great post
thank you very much.

By: shab

shab — Wed, 24 Aug 2011 03:04:12 +0000

Hi Lucas
Great article and examples -thanks.
One issue though, I got his working for my needs on a relatively small dataset but when I tried to scale it up to sort a pl/sql table of around 4 million rows I received the following error:
ORA-22813: operand value exceeds system limits
This error arises on the following statement.
select cast(multiset(select t_pair
(actual,
predicted,
original_index)
from table(l_tbl)
order by predicted desc, original_index asc) as t_pairs)
into l_tbl
from dual;
I know that you said that you hadn’t tested it with a large data set, I guess i just did.Â Â Any suggestions on to sorting larger pl/sql tables?
Thanks
shab

By: Trout

Trout — Fri, 14 May 2010 14:24:16 +0000

Combining this with analytical functions is very useful.Â I am using the technique in a modeling package that uses bulk inserts to speed the processing of large volumes of rows (35 million).Â By using this method I can get the analytical function results without having to go to the DB a second time for updates after the inital inserts.

By: Trout

Trout — Wed, 28 Apr 2010 19:43:12 +0000

Thanks for this.Â Saved me a fair bit of time.

By: Thaha

Thaha — Mon, 12 Oct 2009 13:56:41 +0000

Wonderful example.. Thanks a lot …

By: Daniel

Daniel — Fri, 24 Oct 2008 18:07:48 +0000

Thanks for your simple collection sorting method. I have been looking for a way to do this without relying on an index.

It’s so hard to find clear solutions for what should be simple Oracle tasks. No wonder I usually do things like this on the Java application side.

By: M.Bilal

M.Bilal — Tue, 27 Feb 2007 14:59:34 +0000

It is really great, and lot of thanks for this article.

By: Patrick Sinke

Patrick Sinke — Sun, 27 Aug 2006 13:27:14 +0000

I also encountered a way to do it without the necessity to create a type outside the package (which is annoying):

DECLARE
TYPE typ_sorttabIS TABLE OF NUMBER(1) index by VARCHAR2(100) ;
l_order_tab typ_sorttab;
ln_pos NUMBER(8) ;
lv_input VARCHAR2(100) ;
lv_input_string varchar2(100) ;
lb_doorgaan boolean default TRUE;
lv_result VARCHAR2(100) := ‘;’; — string begint met een ‘;’
BEGIN
lv_input_string := ‘;BLA;DIE;BLOE;TEST;’
— 1e gedeelte leest de inputstring in een array
ln_pos := instr(lv_input_string, ‘;’);
WHILE lb_doorgaan
LOOP
lv_input := substr(lv_input_string, 1, ln_pos-1) ; — alles tot eerstvolgende scheidingsteken
IF lv_input is not null
THEN
— deze controle is nodig omdat de eerste keer een lege string zal opleveren
l_order_tab(lv_input) := 1 ;
END IF;
lv_input_string := substr(lv_input_string, ln_pos + 1) ; — input_string min input
ln_pos := instr(lv_input_string, ‘;’) ;– volgende scheidingsteken
lb_doorgaan := ln_pos > 0 ; — scheidingstekens nog aanwezig
END LOOP ;
— 2e gedeelte voor output
lv_input := l_order_tab.first ;
WHILE lv_input IS NOT NULL
LOOP
lv_result := lv_result || lv_input || ‘;’ ;
lv_input := l_order_tab.next(lv_input) ;
END LOOP ;
–
end;

The trick is too create a table of number with index on the field to be sorted. In this example the array is filled manually from a comma-separated string and sorted by looping through the array in order of index.

By: Kate Johnson

Kate Johnson — Wed, 23 Aug 2006 23:40:52 +0000

Thank you so much for this article, I have been hunting for how to properly use TABLE/CAST and now you made it even easier with TABLE/CAST/MULTISET. Thank you very much. 2 days of searching is now over.

Next, INSERT/UPDATE/DELETE examples….

By: Francois

Francois — Wed, 31 May 2006 12:32:43 +0000

Great !
Another solution to sort a collection of records by using the . (dot) notation:

create or replace TYPE typ_emp_rec AS OBJECT( empno NUMBER(4), ENAME VARCHAR(10) )
/

create or replace TYPE typ_tab_emp_rec AS TABLE OF typ_emp_rec
/

SQL> declare
2 tremp typ_tab_emp_rec := typ_tab_emp_rec( null);
3 tremp2 typ_tab_emp_rec := typ_tab_emp_rec( null);
4 nb pls_integer := 0 ;
5 begin
6
7 tremp.extend(5) ;
8 for i In reverse 1..5 loop
9 nb := nb + 1 ;
10 tremp(nb) := new typ_emp_rec(i, ‘Name’ || to_char(i) ) ;
11 end loop ;
12
13 — output the collection non-sorted –
14 dbms_output.put_line( ‘*** non-sorted collection ***’ ) ;
15 for i In tremp.first .. tremp.last loop
16 dbms_output.put_line( tremp(i).ename ) ;
17 end loop ;
18
19 select cast ( multiset( select t.*
20 from table( tremp ) t
21 order by t.ename
22 ) as typ_tab_emp_rec)
23 into tremp2
24 from dual;
25 — output the collection sorted on ename –
26 dbms_output.put_line( ‘*** sorted collection (field 2) ***’ ) ;
27 for i In tremp2.first .. tremp2.last loop
28 dbms_output.put_line( tremp2(i).ename ) ;
29 end loop ;
30 end ;
31
32 /
*** non-sorted collection ***
Name5
Name4
Name3
Name2
Name1
*** sorted collection (field 2) ***
Name1
Name2
Name3
Name4
Name5