Question

我有一个包含两列（名称和性别）的表。我的表中有4条记录。

Name  Gender
A       Male
B       Female
C       Male
D       Female

我想编写一个SQL查询，将上述数据转换为以下格式。

Male      Female
A           B    
C           D

Answer 1

另一种与Tim相似的可能性，但只需要一个CTE：

with numbered as (
   select name, gender, row_number() over (partition by gender order by name) as rn
   from the_table
)
select f.name as "Female", m.name as "Male"
from numbered f 
  full outer join numbered m on m.rn = f.rn and m.gender = 'Male'
where f.gender = 'Female';

如果每个性别的行数不同，则使用完全外部联接也可以。

Online example

Answer 2

可能就这么简单

SELECT m.Name Male, f.Name Female
FROM t m, t f
WHERE m.Gender = "Male" AND f.Gender = "Female";

但这没有多大意义，我希望你知道自己在做什么。

Answer 3

这是使用CTE的一种选择：

WITH male AS (
    SELECT Name, ROW_NUMBER() OVER (ORDER BY Name) rn
    FROM yourTable
    WHERE Gender = 'Male'
),
female AS (
    SELECT Name, ROW_NUMBER() OVER (ORDER BY Name) rn
    FROM yourTable
    WHERE Gender = 'Female'
)

SELECT m.Name AS Male, f.Name AS Female
FROM male m
INNER JOIN female f
    ON m.rn = f.rn;

在Oracle 11g上将行转换为列

3 个答案:

Demo