带有 CASE 的 PostgresQL ORDER BY 子句用于排序列

Question

我有一个简单的SELECT ORDER BY 查询形式，它使用CASE 创建排序的ID。 我参考了基于https://gist.github.com/cpjolicoeur/3590737 的两种方法并使用了其中一种。

SELECT id FROM tasks t ORDER BY 
CASE 
WHEN t.type = 'TypeA' THEN 1 
WHEN t.type = 'TypeB' THEN 2 
WHEN t.type = 'TypeC' THEN 3 
END, 
CASE 
WHEN t.state = 'Interrupted' THEN 4 
WHEN t.state = 'Terminated' THEN 5 
WHEN t.state = 'Completed' THEN 6
WHEN t.state = 'Killed' THEN 7
WHEN t.state = 'Warning' THEN 8
WHEN t.state = 'Starting' THEN 9
WHEN t.state = 'New' THEN 10
WHEN t.state = 'Running' THEN 11
END, 
modified ASC;

以上查询基于以下条件对 i​​d 进行排序：

1. TypeA 与状态： 中断、终止、完成、终止、警告、启动、新建、运行
2. TypeB 状态： 中断、终止、完成、终止、警告、启动、新建、运行
3. TypeC 状态： 中断、终止、完成、终止、警告、启动、新建、运行

我现在需要根据以下排序条件修改此 sql：

1. TypeA 的状态：Interrupted,Terminated,Completed,Killed
2. TypeB 状态：Interrupted,Terminated,Completed,Killed
3. TypeC 状态：中断、终止
4. TypeA 状态：Warning,Starting,New,Running
5. TypeB 状态：Warning,Starting,New,Running
6. TypeC 状态：Completed,Killed,Warning,Starting,New,Running

请注意“状态”的顺序（如指定）对于“类型”在这里同样重要

我正在尝试修改上面的 sql 以使其符合新标准。作为一个 sql 专家，我正在寻找最有效的方法来重写这个 sql，它也可以在不久的将来适应排序标准的细微变化。

为了进一步阐明下面的共享示例：

样本数据

id  | type  |    state
----+-------+-------------
 1  | TypeC | Completed
 2  | TypeA | Completed
 3  | TypeA | Running
 4  | TypeB | Completed
 5  | TypeB | Running
 6  | TypeC | Terminated
 7  | TypeC | Unknown
 8  | TypeA | Completed
 9  | TypeB | Interrupted
 10 | TypeB | Completed
 11 | TypeB | Interrupted
 12 | TypeC | Killed
 13 | TypeC | Running
 14 | TypeB | Warning
 15 | TypeB | Running
 16 | TypeB | Killed

预期数据

id  | type  |    state
--- +-------+-------------
 1  | TypeA | Completed
 8  | TypeA | Completed
 9  | TypeB | Interrupted
 11 | TypeB | Interrupted
 4  | TypeB | Completed
 10 | TypeB | Completed
 16 | TypeB | Killed
 7  | TypeC | Unknown
 6  | TypeC | Terminated
 3  | TypeA | Running
 14 | TypeB | Warning
 5  | TypeB | Running
 15 | TypeB | Running
 1  | TypeC | Completed
 12 | TypeC | Killed
 13 | TypeC | Running

Answer 1

也许是这样的？

CASE 
WHEN t.type = 'TypeA' AND t.state 
        IN ( 'Interrupted','Terminated','Completed','Killed') 
  THEN 1
WHEN t.type = 'TypeB' AND t.state 
        IN ( 'Interrupted','Terminated','Completed','Killed') 
  THEN 2
..
..

编辑

我建议您创建一个层次结构表，这样您的查询会变得更简单。

CREATE TABLE type_state_hier AS
select *  FROM 
(
 VALUES
(1,'TypeA','Interrupted'),
(2,'TypeA','Terminated'),
(3,'TypeA','Completed'),
(4,'TypeA','Killed'),
(5,'TypeB','Interrupted'),
(6,'TypeB','Terminated'),
(7,'TypeB','Completed'),
(8,'TypeB','Killed'),
(9,'TypeC','Interrupted'),
(10,'TypeC','Terminated'),
(11,'TypeA','Warning'),
(12,'TypeA','Starting'),
(13,'TypeA','New'),
(14,'TypeA','Running'),
(15,'TypeB','Warning'),
(16,'TypeB','Starting'),
(17,'TypeB','New'),
(18,'TypeB','Running'),
(19,'TypeC','Completed'),
(20,'TypeC','Killed'),
(21,'TypeC','Warning'),
(22,'TypeC','Starting'),
(23,'TypeC','New'),
(24,'TypeC','Running')
) As s(rnk,type,state)
;

现在，通过与主表的简单连接来查询它。

select t.* from tasks t 
  join type_state_hier h on 
  h.type=t.type and h.state = t.state
order by h.rnk ,t.id

如果您不想创建表，只需将其用作 CTE（参考演示）

DEMO