Building a query

Question

hi all, consider the following data
id name ldate
1 abc 01-nov-09
1 abc_1 02-jan-10
1 abc 1-feb-10
2 dfk 25-jul-00
2 dfk_1 1-sept-02
second table
id ldate amount
1 01-nov-09 3456
1 17-nov-09 4567
1 03-jan-10
..<more 1>
2 26-jul-00
2 2-sept-02
as you can see abc change name to abc_1 on 02-jan-10 but this is not reflected on the second table.
dfk change name to dfk_1
i trying to figure out a query that will join by id and compare the ldate to present the appropiate name as of that date.
for example
when joining both table the first row should display
1 abc 01-nov-09 --on this date the name was abc
1 abc 17-nov-09 --same reason as above
1 abc_1 3-jan-10 -- symbol change on 03-jan-10
1 abc 2-feb-10 -- symbol back to abc
2 dfk 26-jul-00
2 dfk_1 2sept-02
anybody has any idea how to do this? sample query will be appreciate. both table are join by id

Answer 1

Hi,
are you looking for something like this.
You may have to benchmark it on your data.
Gong forward please post some sample data, also your DB version.
WITH tab_1 AS(
SELECT 1 id1, 'abc' name1,to_date('01-nov-09','dd-mon-rr') date1 FROM dual UNION ALL
SELECT 1, 'abc_1', to_date('02-jan-10','dd-mon-rr') date1 FROM dual UNION ALL
SELECT 1, 'abc', to_date('01-feb-10','dd-mon-rr') date1 FROM dual UNION ALL
SELECT 2, 'dfk', to_date('25-jul-00','dd-mon-rr') date1 FROM dual UNION ALL
SELECT 2, 'dfk_1', to_date('01-sep-02','dd-mon-rr') date1 FROM dual),
tab_2 AS(
SELECT 1 id2, to_date('01-nov-09','dd-mon-rr') date2,3456 amt from dual union all
SELECT 1, to_date('17-nov-09','dd-mon-rr'),  4567 from dual union all
SELECT 1, to_date('03-jan-10','dd-mon-rr'), 1000 from dual union all
SELECT 2, to_date('26-jul-00','dd-mon-rr'), 1000 from dual union all
SELECT 2, to_date('02-sep-02','dd-mon-rr'), 1000 from dual)
SELECT id2,names.name1,amt,date2 FROM
(SELECT id1,name1,date1,
lead(date1) over(PARTITION BY id1 ORDER BY DATE1 ASC) date3
FROM tab_1) names,tab_2
WHERE names.id1=id2 AND date2 BETWEEN date1 AND nvl(date3,date2)Cheers!!!
Bhushan