您需要聚合：

select id,
       sum(case when quarter = 1 then sales end) as q1_sales,
       sum(case when quarter = 2 then sales end) as q2_sales,
       sum(case when quarter = 3 then sales end) as q3_sales,
       sum(case when quarter = 4 then sales end) as q4_sales
from t
group by id;

这就是创建pivot子句的目的：

-- sample data:
with t(id, quarter, sales) as (
   select 1,1,13 from dual union all
   select 1,2,14 from dual union all
   select 1,3,21 from dual union all
   select 1,4,17 from dual union all
   select 2,1,11 from dual union all
   select 2,2,23 from dual union all
   select 2,3,18 from dual union all
   select 2,4,19 from dual 
)
-- query:
select *
from t
pivot(
  sum(sales) 
  for Quarter in (
        1 as Q1
       ,2 as Q2
       ,3 as Q3
       ,4 as Q4)
);

        ID         Q1         Q2         Q3         Q4
---------- ---------- ---------- ---------- ----------
         1         13         14         21         17
         2         11         23         18         19