Write into a single query

Question

Hi,
I'm fetching supplier, Item, qty information from different tables.
Q1: Supplier Name, Quantity are the columns in my select clause, for only one particular item (hard coded).
But I want a single query which fulfills my below 2 requirements:
1. concatenate top 3 suppliers who has ordered this item with qty in descending order.
2. Sum of the quantity of this particular item ordered by all the supplier (not only top 3 suppliers).
for this, i've been executing Q1 twice.
I want to fetch these two requirements in one query!! Any help on this is appreciated.
Thanks,
Santhosh K

Answer 1

Hi, Santhosh,
Sreekanth Munagala wrote:
Hi,
Is this what you are looking for
DDL statements
create table  xx_item_master as
SELECT 10 Supp_id,'IT1' item, 50 quantity FROM DUAL UNION ALL
SELECT 20 Supp_id,'IT1' item, 100 quantity FROM DUAL UNION ALL
SELECT 30 Supp_id,'IT1' item, 150 quantity FROM DUAL UNION ALL
SELECT 40 Supp_id,'IT1' item, 25 quantity FROM DUAL UNION ALL
SELECT 10 Supp_id,'IT2' item, 150 quantity FROM DUAL UNION ALL
SELECT 20 Supp_id,'IT2' item, 100 quantity FROM DUAL UNION ALL
SELECT 30 Supp_id,'IT2' item, 50 quantity FROM DUALQuery
...That's perfect; thanks.
The query below gets the results you want for any one given item, as ypu requested:
WITH   group_by_supplier      AS
     SELECT       supp_id
     ,       ROW_NUMBER () OVER (ORDER BY SUM (quantity) DESC)     AS r_num
     ,       SUM (SUM (quantity)) OVER ()                              AS total_quantity
     FROM       xx_item_master
     WHERE       item     = :target_item
     GROUP BY  supp_id
SELECT     LTRIM ( SYS_CONNECT_BY_PATH (supp_id, ',')
           )               AS supp_list
,     total_quantity
FROM     group_by_supplier
WHERE     CONNECT_BY_ISLEAF     = 1
START WITH     r_num     = 1
CONNECT BY     r_num     = PRIOR r_num + 1
     AND     LEVEL     <= 3;You can easily adapt it to get several (or all) items at once, if you ever need that.