是否有可能在SQLAlchemy中按优先级排序？

Question

有3行

| Name  |  State   |
|  1    |  Busy    |
|  2    |  Online  |
|  3    |  Offline |

我想优先考虑＆＃34;在线＆＃34; ＆GT; ＆＃34;忙＆＃34; ＆GT; ＆＃34;离线＆＃34;

 heroes = HeroModel.query.\
            filter(HeroModel.id.in_(hero_ids)).\
            order_by(???????). \
            all()

我该如何订购？不按字母顺序排列。

Answer 1

在您的选择查询中使用类似的内容

case state
when 'online' then 1 
when 'offline' then 2
else 3
end as rnk

并在此派生列rnk

上使用order by

order by rnk 

Answer 2

您可以在SQLAlchemy中尝试此操作（如果您使用Oracle或MySQL）：

heroes = HeroModel.query.\
          filter(HeroModel.id.in_(hero_ids)).\
          order_by(
           case(
               [(HeroModel.state == "online", 0),
                (HeroModel.state == "busy", 1),
                (HeroModel.state == "offline", 2)],
               else_=3). \
         all()