Oracle 11g Release 2

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CREATE TABLE tab (
   exdate date
 , vendor char(2)
 , product varchar(20)
);
insert into tab values(to_date('2021-08-01','RRRR-MM-DD'), '01', '蘋果');
1 rows affected

insert into tab values(to_date('2021-08-02','RRRR-MM-DD'), '01', '芭樂');
1 rows affected

insert into tab values(to_date('2021-08-03','RRRR-MM-DD'), '01', '水蜜桃');
1 rows affected

insert into tab values(to_date('2021-09-01','RRRR-MM-DD'), '01', '蘋果');
1 rows affected

insert into tab values(to_date('2021-09-02','RRRR-MM-DD'), '01', '西瓜');
1 rows affected

insert into tab values(to_date('2021-09-03','RRRR-MM-DD'), '01', '香蕉');
1 rows affected

insert into tab values(to_date('2021-08-05','RRRR-MM-DD'), '01', '番茄');
1 rows affected

insert into tab values(to_date('2021-08-01','RRRR-MM-DD'), '02', '蘋果');
1 rows affected

insert into tab values(to_date('2021-08-02','RRRR-MM-DD'), '02', '芭樂');
1 rows affected

insert into tab values(to_date('2021-08-03','RRRR-MM-DD'), '02', '水蜜桃');
1 rows affected

SELECT to_char(exdate,'YYYYMM') AS YearMonth,vendor,product,product2
FROM (SELECT exdate,vendor,product,
ROW_NUMBER() OVER (PARTITION BY vendor,to_char(exdate,'YYYYMM') ORDER BY exdate) AS NO,
LEAD(product,1,'') OVER (PARTITION BY vendor,to_char(exdate,'YYYYMM') ORDER BY exdate) AS product2
FROM tab) M
WHERE M.NO = 1


YEARMONTH
VENDOR
PRODUCT
PRODUCT2


202108
01
蘋果
芭樂

202109
01
蘋果
西瓜

202108
02
蘋果
芭樂

YEARMONTH	VENDOR	PRODUCT	PRODUCT2
202108	01	蘋果	芭樂
202109	01	蘋果	西瓜
202108	02	蘋果	芭樂