SQL组三列合为一

Question

我有一个包含三列的表：

[ID]  [name]         [link]
1     sample_name_1  sample_link_1
2     sample_name_2  sample_link_2
3     sample_name_3  sample_link_3

我需要以某种方式将它们分组为一列，所以理想的结果是这样：

[one_column]
1
sample_name_1
sample_name_1
2
sample_name_2
sample_link_2
3
sample_name_3
sample_link_3

您对在Microsoft SQL中的外观和如何完成有任何建议吗？

Answer 1

您可以尝试将VALUES表值构造函数与CROSS APPLY结合使用：

SELECT v.one_column
FROM Table t
CROSS APPLY (VALUES 
  (1, CONVERT(varchar(50), ID)), 
  (2, CONVERT(varchar(50), name)), 
  (3, CONVERT(varchar(50), link))
) v (rn, one_column)
ORDER BY t.ID, v.rn

Answer 2

虽然这是您应该在表示层（即您的应用或网站）中执行的操作，但是可以在SQL中执行此操作：

select one column
from
(
  select cast(id as varchar(10)) as one column, id as sortkey1, 1 as sortkey2 from mytable
  union all
  select name as one column, id as sortkey1, 2 as sortkey2 from mytable
  union all
  select link as one column, id as sortkey1, 3 as sortkey2 from mytable
) unioned
order by sortkey1, sortkey2;