Oracle SQL数据透视查询

Question

我在表格中有数据如下所示:

MONTH VALUE

1     100
2     200
3     300
4     400
5     500
6     600

我想编写一个SQL查询,以便得到如下结果:

MONTH_JAN MONTH_FEB MONTH_MAR MONTH_APR MONTH_MAY MONTH_JUN
100       200       300       400       500       600

Answer 1

Oracle 11g及以上版本

从Oracle 11g开始,您现在可以使用PIVOT运算符来实现该结果:

create table tq84_pivot (
  month number,
  value number
);

insert into tq84_pivot values(1, 100);
insert into tq84_pivot values(2, 200);
insert into tq84_pivot values(3, 300);
insert into tq84_pivot values(4, 400);
insert into tq84_pivot values(5, 500);
insert into tq84_pivot values(6, 600);
--
insert into tq84_pivot values(1, 400);
insert into tq84_pivot values(2, 350);
insert into tq84_pivot values(4, 150);

select 
  *
from
  tq84_pivot
pivot (
   sum (value) as sum_value for
     (month) in (1 as month_jan,
                 2 as month_feb,
                 3 as month_mar,
                 4 as month_apr,
                 5 as month_mai,
                 6 as month_jun,
                 7 as month_jul,
                 8 as month_aug,
                 9 as month_sep,
                10 as month_oct,
                11 as month_nov,
                12 as month_dec)
);

Answer 2

Oracle 9i +支持:

SELECT SUM(CASE WHEN t.month = 1 THEN t.value ELSE 0 END) AS JAN,
       SUM(CASE WHEN t.month = 2 THEN t.value ELSE 0 END) AS FEB,
       SUM(CASE WHEN t.month = 3 THEN t.value ELSE 0 END) AS MAR,
       SUM(CASE WHEN t.month = 4 THEN t.value ELSE 0 END) AS APR,
       SUM(CASE WHEN t.month = 5 THEN t.value ELSE 0 END) AS MAY,
       SUM(CASE WHEN t.month = 6 THEN t.value ELSE 0 END) AS JUN
  FROM YOUR_TABLE t

你只列出了两列 - 这样的东西应该按年分组.

有ANSI PIVOT(和UNPIVOT)语法,但Oracle直到11g才支持它.在9i之前,您必须用Oracle特定的DECODE替换CASE语句.