SQL:选择与UNION,ORDERBY和LIMIT。-SQL:SELECTwithUNION,ORDERBYandLIMIT

4  

That's not how it works, at least in MySQL (you didn't specify). The ORDER operation comes after the data is selected and all UNIONs, GROUP BYs, etc. have been performed.

这不是它的工作原理，至少在MySQL中(您没有指定)。订单操作是在数据被选中之后进行的，所有的工会、BYs等都已经执行了。

See SQL Server: ORDER BY in subquery with UNION for a way around this.

参见SQL Server:通过与UNION进行子查询的顺序来解决这个问题。

21  

if you have a very complex query in SQLite but need to use UNION with ordering, then you can try

如果您在SQLite中有一个非常复杂的查询，但是需要使用UNION与排序，那么您可以尝试。

select * from (
    select * from b ORDER BY date asc
    )
UNION
select * from (
    select * from b ORDER BY name desc
    )
UNION
select * from (
    select * from b ORDER BY gender asc
    )

7  

An order by will affect the ENTIRE union.

一个命令会影响整个联盟。

Anyway, it looks like you want the rows nearest to now. You could try this:

不管怎样，看起来你想要离现在最近的行。你可以试试这个:

SELECT   time, x, y, z 
FROM     db 
ORDER BY ABS(time - now) ASC
LIMIT    10

4  

In "standard" (for some definition of "standard") SQL;

在“标准”(对“标准”)SQL的定义中;

select top 10 *
from (       select time,x,y,z from db where time > now
       union select time,x,y,z from db where time