SQL：将行转换为列

我需要将行的值转换为列-例如：

SELECT s.section_name, 
       s.section_value 
  FROM tbl_sections s

这将产生：

section_name   section_value
-----------------------------
sectionI       One
sectionII      Two
sectionIII     Three

期望输出：

sectionI      sectionII      sectionIII
-----------------------------------------
One           Two            Three

---

用您选择的编程语言在客户端完成这项工作可能更好

要将节名转换为列名，您绝对需要提前知道节名

Oracle 11g的更新答案（使用）：

SELECT * FROM 
  (SELECT section_name, section_value FROM tbl_sections)
PIVOT
  MAX(section_value) 
    FOR (section_name) IN ('sectionI', 'sectionII', 'sectionIII')

WITH
  SELECT section_name, section_value FROM tbl_sections
AS 
  data
SELECT
   one.section_value 'sectionI', 
   two.section_value 'sectionII', 
   three.section_value 'sectionIII'
FROM 
   select selection_value from data where section_name = 'sectionI' one
  CROSS JOIN
   select selection_value from data where section_name = 'sectionII' two
  CROSS JOIN
   select selection_value from data where section_name = 'sectionIII' three

SELECT 
   MAX(DECODE(section_name, 'sectionI', section_value, '')) 'sectionI',
   MAX(DECODE(section_name, 'sectionII', section_value, '')) 'sectionII',
   MAX(DECODE(section_name, 'sectionIII', section_value, '')) 'sectionIII'
FROM tbl_sections

对于旧版本，您可以进行一些自连接：

SELECT * FROM 
  (SELECT section_name, section_value FROM tbl_sections)
PIVOT
  MAX(section_value) 
    FOR (section_name) IN ('sectionI', 'sectionII', 'sectionIII')

WITH
  SELECT section_name, section_value FROM tbl_sections
AS 
  data
SELECT
   one.section_value 'sectionI', 
   two.section_value 'sectionII', 
   three.section_value 'sectionIII'
FROM 
   select selection_value from data where section_name = 'sectionI' one
  CROSS JOIN
   select selection_value from data where section_name = 'sectionII' two
  CROSS JOIN
   select selection_value from data where section_name = 'sectionIII' three

SELECT 
   MAX(DECODE(section_name, 'sectionI', section_value, '')) 'sectionI',
   MAX(DECODE(section_name, 'sectionII', section_value, '')) 'sectionII',
   MAX(DECODE(section_name, 'sectionIII', section_value, '')) 'sectionIII'
FROM tbl_sections

或同时使用最大技巧和“聚合”：

SELECT * FROM 
  (SELECT section_name, section_value FROM tbl_sections)
PIVOT
  MAX(section_value) 
    FOR (section_name) IN ('sectionI', 'sectionII', 'sectionIII')

WITH
  SELECT section_name, section_value FROM tbl_sections
AS 
  data
SELECT
   one.section_value 'sectionI', 
   two.section_value 'sectionII', 
   three.section_value 'sectionIII'
FROM 
   select selection_value from data where section_name = 'sectionI' one
  CROSS JOIN
   select selection_value from data where section_name = 'sectionII' two
  CROSS JOIN
   select selection_value from data where section_name = 'sectionIII' three

SELECT 
   MAX(DECODE(section_name, 'sectionI', section_value, '')) 'sectionI',
   MAX(DECODE(section_name, 'sectionII', section_value, '')) 'sectionII',
   MAX(DECODE(section_name, 'sectionIII', section_value, '')) 'sectionIII'
FROM tbl_sections

---

您好，谢谢您的回答，有没有什么方法我们不知道该部分的名称，会变成列？这将创建一个非常可怕的交叉积，不是吗@斯普雷纳：不，不。不仅仅是SQL。在运行查询之前，需要知道表名、列名等。可能通过PL/SQL使用本机动态SQL。但这相当于“用您选择的编程语言在客户端”这样做。@gfource：如果只有一行，那就没那么可怕了。但是，是的，这不能很好地扩展到许多行和/或列。这不是最佳解决方案，一个轴就足够了。如果有多行的section\u名称为

sectionI

，但值不同，会发生什么情况？是否显示另一行？如果是，第二节和第三节应显示什么？如果每个节名称的条目数不匹配，空列会出现在哪里？从一般意义上讲，你要做的事情并不是很明确。