MySql：保留 UNION ALL 结果中的顺序

Question

我有以下内容：

with
result1 as ( select column1 from table1 order by ... )
result2 as ( select column1 from table2 order by ... )
select * from result1 union all select * from result2;

目的是列出保留顺序的result1 ，然后列出保留顺序的result2 。 但是， union all似乎并没有保留其操作数表的顺序。 我怎样才能达到预期的效果？ 我已经尝试将列添加到有序的result1和result2 ，然后在这个添加的列上对联合结果进行排序，但这对于看起来非常典型的东西来说似乎非常笨拙。 有没有像union all ordered这样的东西？

Answer 1

行。 以下是您如何使用“窗口函数”对其进行排序。 前提是你用的是MySQL 8+

with
result1 as ( 
select column1, ROW_NUMBER() OVER (ORDER BY ...) AS rownum1, 0 AS rownum2, 
from table1 order by ...
),
result2 as ( 
select column1, 0 AS rownum1, ROW_NUMBER() OVER (ORDER BY ...) AS rownum2
from table2 order by ...
),
result as (
select * from result1 
union all
select * from result2 
)
     
select * from result order by rownum2, rownum1