Question

我在PostgreSQL中有一个返回的查询：

id      operation   quantity   date
----------------------------------------
1282    WITHDRAW      20    2015-01-01
541     INCOMING      50    2015-01-01
4788    ACCEPT        17    2015-01-01
4789    ACCEPT        20    2015-01-01
.....

查询顺序按date ...

对记录进行排序

但是，我希望按operation执行二级订单：首先INCOMING，然后是ACCEPT，然后是WITHDRAW。同一操作的记录之间的顺序并不重要：

541     INCOMING      50    2015-01-01
4788    ACCEPT        17    2015-01-01
4789    ACCEPT        20    2015-01-01
1282    WITHDRAW      20    2015-01-01

或

541     INCOMING      50    2015-01-01
4789    ACCEPT        20    2015-01-01
4788    ACCEPT        17    2015-01-01
1282    WITHDRAW      20    2015-01-01

都好。

我无法使用operation列或id列，因为它无法提供所需的结果......

Select ...
from ...
where ...
order by date

如何手动指定我想要的订单..？

我正在寻找类似的SQL语法：

order by date, (operation order by: INCOMING,ACCEPT,WITHDRAW)

Answer 1

通过以下方式为订单使用表达式：

order by date, 
         case operation 
              when 'INCOMING' then 1
              when 'ACCEPT' then 2
              when 'WITHDRAW' then 3
              else 4 -- this is a fallback, anything else will be sorted at the end
         end

Answer 2

从Postgres v9.5开始，可以使用Nicer解决方案。

ORDER BY date, 
     array_position(ARRAY['INCOMING', 'ACCEPT', 'WITHDRAW']::varchar[], operation)

手动指定查询顺序

2 个答案: