使用 PIVOT 的 NULL 字段答案

【问题标题】：NULL fields using PIVOT使用 PIVOT 的 NULL 字段
【发布时间】：2019-11-15 10:52:18
【问题描述】：

我请求您的合作，因为pivot 在一张表上并用null 分隔记录，但仍将字段保留为 0 和NVL

表格

product   | value
----------+-------
Shirts    | 1200
Caps      | 0
Stocks    | 0
Glasses   | 100
Shoes     | 0

科迪戈支点

select * from products
 PIVOT (sum(value)
   for titles in ('product', 'value')) AS pivot_product

结果：

 product  |  Shirts   |  Caps  |    Stocks   | Glasses | Shoes
 ---------+-----------+--------+-------------+---------+----------
   value  |    NULL   |  NULL  |    NULL     |   100   |   NULL
   value  |    1200   |  NULL  |    NULL     |   NULL  |   NULL

预期结果：

 product  |  Shirts   |  Caps  |    Stocks   | Glasses | Shoes
 ---------+-----------+--------+-------------+-------+----------
   valor  |    1200   |  NULL  |    NULL     |  100  |   NULL

可选

 product  |  Shirts   |  Caps  |    Stocks   | Glasses | Shoes
 ---------+-----------+--------+-------------+-------+----------
   valor  |    1200   |    0   |      0      |  100  |    0

【问题讨论】：

标签： sql oracle oracle11g pivot

【解决方案1】：

您需要将列值放入数据透视表中：

Oracle 设置：

CREATE TABLE test_data ( product, value ) AS
SELECT 'Shirts', 1200 FROM DUAL UNION ALL
SELECT 'Caps',      0 FROM DUAL UNION ALL
SELECT 'Stocks',    0 FROM DUAL UNION ALL
SELECT 'Glasses', 100 FROM DUAL UNION ALL
SELECT 'Shoes',     0 FROM DUAL

查询：

SELECT 'value' AS product,
       p.*
FROM   test_data
PIVOT ( SUM( value ) FOR product IN (
  'Shirts'  AS Shirts,
  'Caps'    AS Caps,
  'Stocks'  AS Stocks,
  'Glasses' AS Glasses,
  'Shoes'   AS Shoes
) ) p

输出：

产品 |衬衫 |帽 |股票 |眼镜 |鞋 :-------- | -----: | ---: | -----: | ------: | ----: 价值 | 1200 | 0 | 0 | 100 | 0

db小提琴here

【讨论】：

列是否有可能是动态的而不是手动的？

【解决方案2】：

只需使用条件聚合。它更灵活：

select 'valor' as product,
       sum(case when product = 'Shirts' then value end) as shirts,
       sum(case when product = 'Caps' then value end) as caps,
       sum(case when product = 'Stocks' then value end) as stockes,
       sum(case when product = 'Shirts' then value end) as shirts,
       sum(case when product = 'Glasses' then value end) as glasses,
       sum(case when product = 'Shoes' then value end) as shoes
from test_data;

【讨论】：